Chitosan Veröffentlichungen im April 2009
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1: Pak J Biol Sci 2009 Apr;12(7):574-81
The perspective effects of various seed coating substances on rice seed variety Khao Dawk Mali 105 storability II: the case study of chemical and biochemical properties
Thobunluepop, P, Pan-in, W, Pawelzik, E, Vearasilp, S, Department of Agricultural Technology, Faculty of Technology, Mahasarakham University, Talard Sub-District, Muang District, Maha Sarakham 44000, Thailand.
The aim of this study was to investigate the effects of seed coating substances; chemical fungicide (CA) and biological fungicide polymers [chitosan-lignosulphonate polymer (CL) and eugenol incorporated into chitosan-lignosulphonate polymer (E+CL)] on chemical and biochemical changes of rice seeds cv. KDML 105, which have been studied during storage for 12 months. CA significantly affected the rice seed chemical properties and the associated seed deterioration. ... The biological coated seeds were found to maintain high sugar contents inside the seeds, which resulted high seed storability significantly. In contrast, under fungicide stress (CA), those compounds were lost that directly affected seed vigor during storage.
PMID: 19580014 [found with GoPubMed]
Medical Research / Drug Delivery:
2: Int J Artif Organs 2009 Apr;32(4):224-31
Responses of free radicals to subcutaneous implantation of alginate-chitosan-alginate (ACA) microcapsules in mice
Zhu, Haibao, Xi, Zhaofang, Yang, Shijin, Zhang, Yanhong, Wang, Hong, Guo, Huitian, Zhang, Yao, Chen, Daichi, Guo, Dingzong, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan - China
The objective of this study was to characterize the levels of free radicals in serum and antioxidase activity after microcapsules were implanted into the subcutaneous space of mice. ...These results suggest that nitric oxide plays a role in the specific response to microcapsules. the levels of free radicals rapidly increased immediately following microcapsule transplantation, but they caused only slight cellular damage before the microencapsulated cells were exposed.
PMID: 19569030 [found with GoPubMed]
3: J Drug Target 2009 Apr;17(3):216-24
Augmented inhibitory effect of superoxide dismutase on superoxide anion release from macrophages by chemical modification with polysaccharide and attenuation effects on radiation-induced inflammatory cytokine expression in vitro
Liu, Jinfeng, Teng, Li, Liu, Chunhui, Hu, Likuan, Wang, Yonggang, Liu, Hong, Wang, Fengshan, Institute of Biochemical and Biotechnological Drug, School of Pharmaceutical Science, Jinan, China
To improve the ability of superoxide dismutase (SOD) to suppress reactive oxygen species (ROS)-mediated injury, chemically modified derivatives of SOD with N,N,N-trimethyl chitosan chloride (TMC) and heparin, cationized SOD (TMC-SOD), and anionized SOD (heparin-SOD) were designed and prepared. In this study, the inhibitory effect of TMC-SOD and heparin-SOD on superoxide anion release from macrophages was studied in vitro. Both TMC-SOD and heparin-SOD exhibited excellent inhibitory effects on superoxide anion release from macrophages, and the effects of TMC-SOD surpassed those of native SOD and heparin-SOD. The effects of TMC-SOD and heparin-SOD on inflammatory cytokine expression in vitro were also evaluated. The results showed that both TMC-SOD and heparin-SOD could significantly lower the levels of transforming growth factor-beta1 (TGF-beta1) and interleukine-1beta (IL-1beta) expressed by irradiated 3T3 fibroblasts. These results demonstrated that cationic polysaccharide or anionic polysaccharide SOD derivatives might be useful in the prevention and treatment of ROS-mediated inflammatory diseases. This study also demonstrated that chemical modification of SOD, especially cationization, greatly enhanced SOD's intracellular delivery and, consequently, produced a significant protective effect against ROS-mediated injury.
PMID: 19558361 [found with GoPubMed]
4: Indian J Med Res 2009 Apr;129(4):382-9
Signal transduction pathway involved in the ex vivo expansion of limbal epithelial cells cultured on various substrates
Sudha, Balasubramanian, Jasty, Srilatha, Krishnan, Sasirekha, Krishnakumar, Subramanian, L&T Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
BACKGROUND & OBJECTIVE: Ex vivo expansion of the limbal epithelial cells activates the nerve growth factor (NGF) mediated downstream signal transduction pathway. It is not clear as to which factors control the stemness of the corneal limbal stem cells, i.e., the maintenance of stem cell properties. It is likely that various signaling pathways are involved, including Notch, Wnt and NGF signaling, etc. In the present study, we investigated the activation of phosphoinositide-3-kinase (PI3K) pathway on cells cultured over the chitosan matrix, chitosan silver matrix, chitosan gold matrix, intact and denuded human amniotic membrane (HAM). ... INTERPRETATION & CONCLUSION: The ex vivo expansion of human limbal epithelial progenitor cells on intact HAM was mediated by PI3K/Akt/FKHRL1 pathway, which is known to govern cell survival, and the mitogen-activated protein kinase (MAPK) pathway, known to control the cell mitosis.
PMID: 19535832 [found with GoPubMed]
5: Drug Deliv 2009 Apr;16(3):176-81
Chitosan glutamate hydrogels with local anesthetic activity for buccal application
Pignatello, R, Basile, L, Puglisi, G, Dipartimento di Scienze Farmaceutiche, Università degli Studi di Catania, viale A. Doria, 6, Catania I-95125, Italy
Hydrogels for the buccal application of the anesthetic drug lidocaine hydrochloride (LDC) were prepared using chitosan glutamate (CHG), a soluble salt of chitosan, or a binary mixture of CHG and glycerin, at different weight ratios. The in vitro drug release was studied at the pH value of saliva to assess the effect of the different formulations on drug delivery. The anesthetic activity of mucoadhesive LDC-CHG hydrogels was assessed in vivo after application on the buccal mucosa, compared to commercial semisolid formulations containing the same drug. LDC-loaded hydrogels can be proposed for the symptom relief of aphthosis or other painful mouth diseases.
PMID: 19514978 [found with GoPubMed]
6: Drug Deliv 2009 Apr;16(3):160-6
Preparation of honokiol-loaded chitosan microparticles via spray-drying method intended for pulmonary delivery
Li, Xingyi, Guo, QingFa, Zheng, XiuLing, Kong, XiangYe, Shi, Shuai, Chen, Lijuan, Zhao, Xia, Wei, YuQuan, Qian, ZhiYong, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, PR China
It has been demonstrated that spray-drying is a powerful method to prepare dry powders for pulmonary delivery. This paper prepared dispersible dry powders based on chitosan and mannitol containing honokiol nanoparticles as model drug. The results showed that the prepared microparticles are almost spherical and have appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters was between 2.8-3.3 microm and tapped density ranging from 0.14-0. 18 g/cm(3)). Moreover, surface morphology and aerodynamic properties of the powders were strongly affected by the content of mannitol. Fourier transform infra-red (FTIR) spectrum of powders indicated that the honokiol nanoparticles were successfully incorporated into microparticles. In vitro drug release profile was also observed. The content of mannitol in powders significantly influenced the release rate of honokiol from matrices.
PMID: 19514976 [found with GoPubMed]
7: Drug Deliv 2009 Apr;16(3):135-44
DNA/chitosan nanocomplex as a novel drug carrier for doxorubicin
Cheng, Xiaoyun, Zhang, Feng, Zhou, Guangxin, Gao, Shuying, Dong, Lei, Jiang, Wei, Ding, Zhi, Chen, Jiangning, Zhang, Junfeng, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China
The present study was to investigate the potentials of DNA/chitosan nanocomplexes as a carrier for small drug delivery. Two highly water-soluble chitosans (87 kDa and 18 kDa) were prepared and labeled with fluorescein isothiocyanate (FITC). DNA/chitosan nanocomplexes were prepared by mixing salmon testes DNA and the FITC labeled chitosan (FITC-chitosan) and their biophysical properties and biodistribution in vivo were then investigated. The molecular weight of chitosan and the ratio of the positive amino group of chitosan to the negative phosphate group of DNA (N/P ratio) influenced the physical properties of the nanocomplexes. The fluorescence intensity of both types of the free FITC-chitosan decreased rapidly within 4 hr post-injection. In contrast, the DNA/chitosan nanocomplexes were accumulated in the liver and kidneys and remained at a relatively high stable level in these tissues and in blood up to 24 hr post-injection. This study also assessed the stability of the anti-cancer drug doxorubicin (DOX) when it was conjugated to chitosan to form a chitosan-doxorubicin conjugate (chi-DOX), which was then mixed with DNA to form a DNA/chitosan-doxorubicin nanocomplex (DNA/chi-DOX). Both the chi-DOX and DNA/chi-DOX complexes exerted cytotoxic effects on HeLa, HepG2, QGY-7703, and L02 cells, while the non-malignant L02 cells were less sensitive to the DNA-containing complex than to the chi-DOX complex, suggesting possible selectivity. Studies in tumor-bearing animals demonstrated that DNA/chi-DOX could efficiently deliver doxorubicin to the tumor and liver, implying that the DNA/chitosan nanocomplex may represent a novel drug carrier.
PMID: 19514973 [found with GoPubMed]
8: J Hazard Mater 2009 Apr;
Photocatalytic decolorization and degradation of Congo Red on innovative crosslinked chitosan/nano-CdS composite catalyst under visible light irradiation
Zhu, H, Jiang, R, Xiao, L, Chang, Y, Guan, Y, Li, X, Zeng, G, Department of Environmental Engineering, Taizhou University, Linhai 317000, PR China; College of Resource and Environmental Science, Wuhan University, Wuhan 430072, PR China
The crosslinked chitosan/nano-CdS (CS/n-CdS) composite catalyst prepared by simulating bio-mineralization process was extensively characterized by FT-IR spectra, XRD, SEM, TEM and TGA. An azo dye, Congo Red (CR), was used as model pollutant to study its photocatalytic activity under visible light irradiation. The influences of catalyst amount, initial CR concentrations, pH of the reaction solution and different anions on CR decolorization and degradation reaction kinetics were investigated. Results of characterization indicated the successful formation of hexagonal phase of CdS on raw chitosan under mild conditions. The photocatalytic degradation was found to follow a pseudo-first-order kinetics according to Langmuir-Hinshelwood (L-H) model. The dye could be decolorized more efficiently in acidic media than alkaline media. The presence of NO(3)(-) accelerated evidently the degradation of CR, while the other chosen anions (Br(-), SO(4)(2-) and Cl(-)) had an inhibitory effect on the decolorization of CR, of which the inhibitory effect of Cl(-) was the most pronounced. UV-vis spectra were analyzed to indicate that degradation of CR in the solution was the break up of the NN bonds and degradation of aromatic fragment in this reaction system. The recycling experiments confirmed the relative stability of the catalyst.
PMID: 19477069 [found with GoPubMed]
9: Micron 2009 Apr;
EVA-enhanced embedding medium for histological analysis of 3D porous scaffold material
Lim, J I, Lee, Y K, Department of Dental Biomaterials Science, Dental Research Institute and BK21 Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
When sectioning a 3D porous scaffold made of a soft elastomeric material embedded in paraffin medium, it is not easy to obtain a section because of the different mechanical properties of the paraffin and tissue/scaffold. We describe a new embedding material for histological analysis of various biomaterials that is composed of paraffin and ethylene vinyl acetate (EVA) resin (0, 3, 7, and 13wt.%). 3D porous poly(l-lactide-varepsilon-caprolactone) (PLCL) and chitosan scaffolds were fabricated to test the sectioning efficiency of the paraffin/EVA embedding material. The new embedding material was characterized by rheological analysis and solvent solubility testing in xylene and n-hexane. The hydrophilicity of the new material was assessed by contact angle measurement and its surface roughness was measured using AFM analysis. The staining efficiency of sections embedded in a paraffin/EVA mixture was determined by eosin staining of the chitosan scaffold and chitosan/collagen hybrid scaffold using a fluorescently labeled collagen. Section roughness decreased with increasing EVA content. The softening temperature of the paraffin/EVA mixture was similar to that of paraffin (50-60 degrees C by rheometer). The paraffin/EVA mixture dissolved completely in xylene after 30min at 50 degrees C, and after 30min in n-hexane at 60 degrees C. Therefore, the new embedding medium can be used for histological analysis of various biomaterials and natural tissues.
PMID: 19473850 [found with GoPubMed]
10: J Eur Acad Dermatol Venereol 2009 Apr;
Improvement of psoriatic onychodystrophy by a water-soluble nail lacquer
Cantoresi, F, Sorgi, P, Arcese, A, Bidoli, A, Bruni, F, Carnevale, C, Calvieri, S, Department of Dermatology, 'La Sapienza' University, Rome, Italy
Abstract Background There is a strong need for effective products, simple to use and safe for a chronic use in the management of nail psoriasis. Recently, a non-drug, water-soluble nail lacquer became available, containing hydroxypropyl chitosan (HPCH), horsetail extract (Equisetum arvense) and methylsulphonyl-methane (DMSO(2)). This product was effective in strengthening the nails and reducing fragility and roughness in brittle nails. A clinical trial was performed to verify whether this product was able to improve nail psoriatic signs and appearance. Patients and methods Thirty adult patients affected by mild to moderate symmetric psoriasis of the matrix and/or of the nail bed in at least one fingernail diagnosed more than 6 months before screening and with negative mycology findings were recruited. The nail lacquer was applied once daily on the affected fingernails of the left hand for 24 consecutive weeks. The right hand was used as control. The extent and severity of nail psoriasis was assessed on a target fingernail by means of the recently proposed Nail Psoriasis Severity Index (NAPSI) score. The value at baseline was 2.83 (+/- 0.99). At the end of treatment, the patients judged the treatment effect and their willing to continue product application. Adverse events were carefully recorded. Results Overall, 28 patients were included in the efficacy analysis. At the end of treatment, results showed a 72% reduction in pitting, 66% reduction in leukonychia, 63% reduction in onycholysis and a reduction of 65% in NAPSI score compared to baseline, respectively. No changes were observed in the untreated nails. Patients' treatment evaluation was classified as very satisfying or good by 78.6% of patients. The acceptability of the treatment was excellent in all patients both for the easiness and for the organoleptic characteristics of the product and 75% of them decided to continue the application after the end of the study. No adverse reactions were reported. Conclusion In our experience, the new water-soluble nail lacquer proved to be effective in decreasing signs and symptoms of nail dystrophy in psoriatic patients. The effect was particularly evident on NAPSI and on pitting. The product was very well accepted by the patients. Conflict of Interest None declared.
PMID: 19470045 [found with GoPubMed]
11: Int J Pharm 2009 Apr;
Chitosan-hyaluronic acid nanoparticles loaded with heparin for the treatment of asthma
Oyarzun-Ampuero, F A, Brea, J, Loza, M I, Torres, D, Alonso, M J, Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
The purpose of this study was to produce mucoadhesive nanocarriers made from chitosan (CS) and hyaluronic acid (HA), and containing the macromolecular drug heparin, suitable for pulmonary delivery. For the first time, this drug was tested in ex vivo experiments performed in mast cells, in order to investigate the potential of the heparin-loaded nanocarriers in antiasthmatic therapy. CS and mixtures of HA with unfractionated or low-molecular-weight heparin (UFH and LMWH, respectively) were combined to form nanoparticles by the ionotropic gelation technique. The resulting nanoparticles loaded with UFH were between 162 and 217nm in size, and those prepared with LMWH were 152nm. The zeta potential of the nanoparticle formulations ranged from +28.1 to +34.6mV, and in selected nanosystems both types of heparin were associated with a high degree of efficiency, which was approximately 70%. The nanosystems were stable in phosphate buffered saline (PBS), pH 7.4, for at least 24h, and released 10.8% of UFH and 79.7% of LMWH within 12h of incubation. Confocal microscopy experiments showed that fluorescent heparin-loaded CS-HA nanoparticles were effectively internalized by rat mast cells. Ex vivo experiments aimed at evaluating the capacity of heparin to prevent histamine release in rat mast cells indicated that the free or encapsulated drug exhibited the same dose-response behaviour.
PMID: 19467809 [found with GoPubMed]
12: Aust Endod J 2009 Apr;35(1):29-33
Susceptibility of Candida albicans and Enterococcus faecalis to Chitosan, Chlorhexidine gluconate and their combination in vitro
Ballal, N V, Kundabala, M, Bhat, K S, Acharya, S, Ballal, M, Kumar, R, Prakash, P Y, Manipal College of Dental Sciences, Manipal, Karnataka, India
The aim of the present study was to analyse the sustain release of Chlorhexidine with Chitosan and to investigate the antimicrobial activity of 2% Chlorhexidine gel, 2% Chitosan gel and their combination against Candida albicans and Enterococcus faecalis. Sustain release of Chlorhexidine with Chitosan was determined using UV spectrophotometer. Then the inoculae of these organisms were used to make the lawn culture on sabouraud's dextrose agar and blood agar plates. Wells were prepared in these lawn cultures and filled with 2% Chlorhexidine gel, 2% Chitosan gel and their combination. The agar plates were incubated overnight at 37 degrees C and the zone of inhibition was examined after 48 h. Release of Chlorhexidine with Chitosan was better than plain Chlorhexidine release. Combination of Chlorhexidine and Chitosan showed maximum inhibitory zone for C. albicans (25.2 mm) and E. faecalis (26.0 mm). Plain Chlorhexidine gel showed intermediate inhibitory zone for C. albicans (20.6 mm) and E. faecalis (21.4 mm) and plain Chitosan gel showed minimum inhibitory zone for C. albicans (16.6 mm) and E. faecalis (11.0 mm). Carbopol which served as control did not have any antimicrobial effect. The present study suggests that 2% Chlorhexidine gel in combination with 2% Chitosan gel has the highest antimicrobial effect against C. albicans and E. faecalis compared with 2% Chlorhexidine gel or 2% Chitosan gel alone.
PMID: 19452677 [found with GoPubMed]
13: J Nanosci Nanotechnol 2009 Apr;9(4):2566-73
Synthesis, properties, and surface enhanced Raman scattering of gold and silver nanoparticles in chitosan matrix
Wei, Dongwei, Qian, Weiping, Wu, Dajian, Xia, Yan, Liu, Xiaojun, State Key Laboratory of Bioelectronics, Department of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, P. R. China
We present here a facile route to in-situsynthesis of free-standing metal (gold or silver) nanoparticles-embedded chitosan films by thermal treatment. The produced nanoparticles were confirmed by UV-vis spectroscopy and transmission electron microscopy (TEM). Interestingly, an exquisite dendritic structure was observed in the resulting silver-chitosan film, which was not present in pure chitosan and gold-chitosan samples. We speculated that the formation of dendritic structures may be due to the presence of nano-sized silver particles which has an influence on the crystallization behavior and thereby the morphology of biopolyer chitosan. The application of the as-prepared metal-chitosan films in surface-enhanced Raman spectroscopy (SERS) was investigated by using Rhodamine 6G (R6G) as probe molecules. It was found that the resultant metal-chitosan samples, especially silver-chitosan one, could be used as SERS substrates exhibiting excellent enhancement ability.
PMID: 19438003 [found with GoPubMed]
14: J Nanosci Nanotechnol 2009 Apr;9(4):2558-65
Preparation of stable chitosan-carboxymethyl dextran nanoparticles
Lin, Yi-Sheng, Renbutsu, Eiko, Morimoto, Minoru, Okamura, Yasuhiko, Tsuka, Takeshi, Saimoto, Hiroyuki, Okamoto, Yoshiharu, Minami, Saburo, Tottori University (United Graduate School, Yamaguchi University), 4-101 Koyama-Minami, Tottori 680-8553, Japan
Chitosan-carboxymethyl dextran nanoparticles (CHI-CMD NPs) were prepared by the formation of polyelectrolyte complex via the interaction of the positive charged amino group of chitosan and the negative charged carboxyl group of carboxymethyl dextran. Biocompatible organic reagents such as lactic acid, phosphate-buffered saline, and carbonate-bicarbonate buffer were used to make CHI-CMD NPs. The pH value of narrowly distributive CHI-CMD NP suspension was close to the physiological value of 6.8, which made it possible for it to be directly applied in an in vitro test without further additional operations. In the presence of sugars (30 mM), the colloidal stability of CHI-CMD NPs could be extended to 5 to 7 days when the particle size could be maintained within a nanometer scale, while the addition of xylose or lactose was found to most effectively extend the colloidal stability of CHI-CMD NPs to 10 days. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis revealed that the structural integrity of CHI-CMD NPs was not destroyed after high steam pressure sterilization (121 degrees C, 30 min), which confirmed the autoclavable property of CHI-CMD NPs.
PMID: 19438002 [found with GoPubMed]
15: Pharmazie 2009 Apr;64(4):284-6
Composite microspheres induce the sustained release and the control of the initial release of water soluble drugs
Chen, G, He, C X, Xu, D H, Liu, L, Zhang, F J, Xu, J Y, Zheng, C H, Gao, J Q, Yan, M, Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, China
Although epidural analgesia may provide adequate pain relief and minimize systemic side effects, long-term, even permanent placement of epidural catheter for chronic or cancer-related pain management carries a potential risk of both superficial and deep infection. The development of antibiotics microspheres that could be dwelled in epidural drug-delivery devices is likely to achieve a significant advance allowing antibiotics given by the intradiscal route to control catheter-related infections. In the present study, the composite microspheres composed of double-walled microcapsules and PLGA were constructed for encapsulating water-soluble antibiotics, cefazolin. The results show that these microspheres could efficiently control the initial release of drug, which was only 3.0% at 2 h. Cefazolin encapsulated in the composite microspheres released gradually nearly in a constant rate in the first 16 days, and still maintained a relative fast rate in the next 14 days, indicating that composite microspheres could improve the incomplete release of entrapped drugs.
PMID: 19435149 [found with GoPubMed]
16: Pharmazie 2009 Apr;64(4):232-7
Enhanced permeability of the urinary bladder wall: the role of polymer charge
Kerec Kos, M, Bogataj, M, Mrhar, A, Faculty of Pharmacy, University of Ljubljana, Slovenia
The urothelium is usually impermeable to substances present in the urine. In the current work the possibility of using different absorption enhancers in the development of intravesical drug delivery systems was explored. To establish the role of the polymer charge on its ability to improve bladder wall permeability, cationic poly-L-arginine, anionic NaCMC and alginate as well as nonionic HPC and HPMC were tested. The permeability experiments were performed on isolated pig urinary bladders. We established that the charge of the polymer affects its ability to enhance the permeability of the urinary bladder wall, but to a limited extent. Positively charged polymers were the most promising absorption enhancers for the urinary bladder wall. In order to significantly enhance the permeability of the bladder wall, higher concentrations of poly-L-arginine were needed compared to chitosan. Moreover, chitosan reached the plateau of its absorption enhancement effect after 60 min, while poly-L-arginine increased the permeability continuously over 90 min. In contrast to polycarbophil, two other anionic polymers, NaCMC and alginate, did not significantly enhance the permeation of pipemidic acid into the tissue. Interactions between the polymers and the drug might prevail over the potential effect of NaCMC and alginate on tissue permeability. Furthermore, for the nonionic polymers HPMC and HPC an insignificant influence on bladder wall permeability was determined. Therefore, the selection of absorption enhancers for intravesical drug delivery systems is limited and cannot be done only on the basis of polymer charge.
PMID: 19435140 [found with GoPubMed]
17: Acta Biomater 2009 Apr;
Synthesis and characterization of collagen/hyaluronan/chitosan composite sponges for potential biomedical applications
Lin, Y C, Tan, F J, Marra, K G, Jan, S S, Liu, D C, Department of Animal Science, National Chung-Hsing University, 250 Kao Kuang RD, Taichung 40227, Taiwan, China
Cells, scaffolds and growth factors are three main components of a tissue-engineered construct. Collagen type I, a major protein of the extracellular matrix (ECM) in mammals, is a suitable scaffold material for regeneration. Another important constituent of the ECM, hyaluronic acid (hyaluronan, HA), has been used for medical purposes due to its hydrogel properties and biodegradability. Chitosan is a linear polysaccharide comprised of beta1- to beta4-linked d-glucosamine residues, and its potential as a biomaterial is based on its cationic nature and high charge density in solution. This study was conducted to evaluate the characteristics of scaffolds composed of different ratios of type I comb collagen and chitosan with added HA in order to obtain the optimum conditions for the manufacture of collagen-hyaluronan-chitosan (Col-HA-Ch; comprising collagen, HA and chitosan mixed in different ratios: 10:1:0, Col10HACh0; 9:1:1, Col9HACh1; 8:1:2, Col8HACh2; 7:1:3, Col7HACh3; 6:1:4, Col6HACh4; and 5:1:5, Col5HACh5) composite porous scaffolds. Microstructural observation of the composite scaffolds was performed using scanning electron microscopy. The mean pore diameters ranged from 120 to 182mum and decreased as the chitosan composition increased. All scaffolds showed high pore interconnectivity. Swelling ratio measurements showed that all specimens could bind 35- to 40-fold of physiological fluid and still maintain their form and stability. For tensile strength, the optimal ratio of collagen and chitosan was 9:1. Thermal stability was investigated using a differential scanning calorimeter and showed that Col5HACh5 and Col6HACh4 were significantly more stable than the other groups. In enzymatic sensitivity, a steady increase in the biostability of the scaffolds was achieved as the chitosan concentration was increased. In biocompatibility testing, the proliferation of the fibroblasts cultured in Co-HA-Ch tri-copolymer scaffolds was high. Overall, we observed the 9:1:1 mixing ratio of collagen, hyaluronan and chitosan to be optimal for the manufacture of complex scaffolds. Furthermore, Col-HA-Ch tri-polymer scaffolds, especially Col9HACh1, could be developed as a suitable scaffold material for tissue engineering applications.
PMID: 19427824 [found with GoPubMed]
18: Nanotechnology 2009 Apr;20(13):135102
Magnetic chitosan nanoparticles as a drug delivery system for targeting photodynamic therapy
Sun, Yun, Chen, Zhi-Long, Yang, Xiao-Xia, Huang, Peng, Zhou, Xin-Ping, Du, Xiao-Xia, Department of Pharmaceutical Science and Technology, College of Chemistry and Biology, Donghua University, Shanghai 201620, People's Republic of China
Photodynamic therapy (PDT) has become an increasingly recognized alternative to cancer treatment in clinic. However, PDT therapy agents, namely photosensitizer (PS), are limited in application as a result of prolonged cutaneous photosensitivity, poor water solubility and inadequate selectivity, which are encountered by numerous chemical therapies. Magnetic chitosan nanoparticles provide excellent biocompatibility, biodegradability, non-toxicity and water solubility without compromising their magnetic targeting. Nevertheless, no previous attempt has been reported to develop an in vivo magnetic drug delivery system with chitosan nanoparticles for magnetic resonance imaging (MRI) monitored targeting photodynamic therapy. In this study, magnetic targeting chitosan nanoparticles (MTCNPs) were prepared and tailored as a drug delivery system and imaging agents for PS, designated as PHPP. Results showed that PHPP-MTCNPs could be used in MRI monitored targeting PDT with excellent targeting and imaging ability. Non-toxicity and high photodynamic efficacy on SW480 carcinoma cells both in vitro and in vivo were achieved with this method at the level of 0-100 microM. Notably, localization of nanoparticles in skin and hepatic tissue was significantly less than in tumor tissue, therefore photosensitivity and hepatotoxicity can be attenuated.
PMID: 19420486 [found with GoPubMed]
19: Shanghai Kou Qiang Yi Xue 2009 Apr;18(2):178-82
Effects of enamel matrix proteins loaded in chitosan thermosensitive hydrogel on bone marrow stromal cells in vitro
Wu, Guang-Sheng, Zhang, Yi-Wen, Wang, Xin-Wen, Ma, Zhi-Wei, Cao, Min, Wang, Qin-Tao, Department of Periodontology and Oral Medicine,School of Stomatology, Fourth Military Medical University. Xi'an 710032, Shanxi Province, China.E-mail:
PURPOSE: To investigate the effects of enamel matrix proteins (EMPs ) on proliferation, alkaline phosphate (ALP) activity of bone marrow stromal cells (BMSCs) seeded on the scaffold of chitosan thermosensitive hydrogel. METHODS: Chitosan thermosensitive hydrogel was prepared and its slow-releasing effect of EMPs was checked by coomassie blue staining kit. Rat BMSCs were obtained from rat bone marrow aspiration and cultured in DMEM medium with 10% fetal bovine serum (FBS). Rat BMSCs were exposed to various concentrations of EMPs (0,50,100 and 150mug/mL) and their proliferation rates were assessed by MTT assay. The proliferation rates and ALP activity of rat BMSCs were examined by MTT assay and ALP kit when BMSCs cultured on the scaffolds of chitosan thermosensitive hydrogel loading with or without 100mug/mL EMPs .The data was statistically analyzed with SPSS11.0 software package for a parametric one-way analysis of variance (ANOVA) and two-sample t test. RESULTS: The release of EMPs in chitosan thermosensitive hydrogel lasted for more than 3 weeks. In DMEM medium, 50mug/mL EMPs significantly enhanced BMSCs proliferation from day 3 over the experiment(P<0.01). In chitosan thermosensitive hydrogel scaffolds loading 100mug/mL EMPs, both the proliferation at day 3 and 5 (P<0.05)and the ALP activity at day 7 (P<0.05) and 9(P<0.01) of BMSCs in the experiment were promoted. CONCLUSION: EMPs loaded on the chitosan thermosensitive hydrogel exhibits significant effects on proliferation and ALP activity of rat BMSCs. Supported by Science Development Plan of Shanxi Province(Grant No. 2006 K14-G3).
PMID: 19417996 [found with GoPubMed]
20: J Hazard Mater 2009 Apr;
Removal of Cu(2+) and turbidity from wastewater by mercaptoacetyl chitosan
Chang, Q, Zhang, M, Wang, J, School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Anning West Road 88, Lanzhou, Gansu, 730 070, China
A macromolecule heavy metal flocculant mercaptoacetyl chitosan (MAC) was prepared by reacting chitosan with mercaptoacetic acid. In preliminary experiments, the flocculation performance of MAC was evaluated by using wastewater containing Cu(2+) or/and turbidity. Some factors which affect the removal of Cu(2+) and turbidity were also studied. The experimental results showed that: (1) MAC can remove both Cu(2+) and turbidity from wastewater. The removal efficiency of Cu(2+) by using MAC combined with hydrolyzed polyacrylamide is higher than that by only using MAC, the removal efficiency of Cu(2+) reaches above 98%; (2) when water sample containing not only Cu(2+) but also turbidity-causing substance, the removal efficiency of both Cu(2+) and turbidity will be promoted by the cooperation effect of each other, the residual concentration of Cu(2+) reaches below 0.5mgL(-1) and the turbidity reaches below 3NTU, Cu(2+) is more easily removed by MAC when turbidity is higher; (3) the removal efficiency of Cu(2+) increases with the increase in pH value, contrarily removal efficiency of turbidity decreases with the increase in pH value.
PMID: 19414213 [found with GoPubMed]
21: J Plant Physiol 2009 Apr;
Benzaldehyde dehydrogenase from chitosan-treated Sorbus aucuparia cell cultures
Gaid, M M, Sircar, D, Beuerle, T, Mitra, A, Beerhues, L, Institute of Pharmaceutical Biology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
Cell cultures of Sorbus aucuparia respond to the addition of chitosan with the accumulation of the biphenyl phytoalexin aucuparin. The carbon skeleton of this inducible defense compound is formed by biphenyl synthase (BIS) from benzoyl-CoA and three molecules of malonyl-CoA. The formation of benzoyl-CoA proceeds via benzaldehyde as an intermediate. Benzaldehyde dehydrogenase (BD), which converts benzaldehyde into benzoic acid, was detected in cell-free extracts from S. aucuparia cell cultures. BD and BIS were induced by chitosan treatment. The preferred substrate for BD was benzaldehyde (K(m)=49muM). Cinnamaldehyde and various hydroxybenzaldehydes were relatively poor substrates. BD activity was strictly dependent on the presence of NAD(+) as a cofactor (K(m)=67muM).
PMID: 19409654 [found with GoPubMed]
22: Biotechnol Bioeng 2009 Apr;
Antioxidant and antibacterial activities of eugenol and carvacrol-grafted chitosan nanoparticles
Chen, F, Shi, Z, Neoh, K G, Kang, E T, Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260, Singapore; telephone: 65-65162176; fax: 65-67791936
Essential oils are known to possess antimicrobial and antioxidant activity while chitosan is a biocompatible polymer with antibacterial activity against a broad spectrum of bacteria. In this work, nanoparticles with both antioxidant and antibacterial properties were prepared by grafting eugenol and carvacrol (two components of essential oils) on chitosan nanoparticles. Aldehyde groups were first introduced in eugenol and carvacrol, and the grafting of these oils to chitosan nanoparticles was carried out via the Schiff base reaction. The surface concentration of the grafted essential oil components was determined by X-ray photoelectron spectroscopy (XPS). The antioxidant activities of the carvacrol-grafted chitosan nanoparticles (CHCA NPs) and the eugenol-grafted chitosan nanoparticles (CHEU NPs) were assayed with diphenylpicrylhydrazyl (DPPH). Antibacterial assays were carried out with a representative gram-negative bacterium, Escherichia coli (E. coli) and a gram-positive bacterium, Staphylococcus aureus (S. aureus). The grafted eugenol and carvacrol conferred antioxidant activity to the chitosan nanoparticles, and the essential oil component-grafted chitosan nanoparticles achieved an antibacterial activity equivalent to or better than that of the unmodified chitosan nanoparticles. Cytotoxicity assays using 3T3 mouse fibroblast showed that the cytotoxicity of CHEU NPs and CHCA NPs were significant lower than those of the pure essential oils. Biotechnol. Bioeng. (c) 2009 Wiley Periodicals, Inc.
PMID: 19408318 [found with GoPubMed]
23: J Pharm Sci 2009 Apr;
The role of mucoadhesion of trimethyl chitosan and PEGylated trimethyl chitosan nanocomplexes in insulin uptake
Jintapattanakit, A, Junyaprasert, V B, Kissel, T, Department of Pharmacy, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayutthaya, Bangkok 10400, Thailand
The aim of this work was to investigate the role of mucoadhesion in the insulin uptake of nanocomplexes (NC) based of trimethyl chitosan (TMC) and poly(ethylene glycol) (PEG)-graft-TMC copolymers. Self-assembled insulin NC were prepared by polyelectrolyte complexation. The effects of PEGylation and positive charge density on mucoadhesion were assessed using a mucin assay and mucus-secreting HT29-MTX-E12 (E12) monolayers. The behaviors of corresponding insulin NC after adhesion to E12 were also established. All PEGylated TMC copolymers showed significantly higher levels of adhesion to mucus than unmodified TMC. The copolymer composed of 298 PEG chains per TMC macromolecules exhibited the highest level of mucoadhesion, being 3.4 times higher than TMC. The higher mucoadhesive properties of PEGylated TMC copolymers resulted from the synergistic effects of interpenetration of PEG chains into the mucus and electrostatic interaction between positive charged TMC and anionic glycoproteins present in the mucus layer. Compared to TMC, insulin NC based on PEGylated TMC copolymers demonstrated no evidence of insulin uptake improvement due to complete release of insulin from NC after adhering to mucus. CLSM revealed the localization of TMC and its corresponding insulin NC at cell surface membranes of E12. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci.
PMID: 19408295 [found with GoPubMed]
24: Acta Biomater 2009 Apr;
Enhanced angiogenesis of porous collagen scaffolds by incorporation of TMC/DNA complexes encoding vascular endothelial growth factor
Mao, Z, Shi, H, Guo, R, Ma, L, Gao, C, Han, C, Shen, J, Key Laboratory of Macromolecular Synthesis and Functionalization, Ministry of Education, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
Angiogenesis of an implanted construct is one of the most important issues in tissue engineering and regenerative medicine, and can often take as long as several weeks. The vascular endothelial growth factor (VEGF) shows a positive effect on enhancing angiogenesis in vivo. But the incorporation of growth factors has many limitations, since they typically have half-lives only on the order of minutes. Therefore, in this work the DNA encoding VEGF was applied to enhance the angiogenesis of a collagen scaffold. A cationic gene delivery vector, N,N,N-trimethyl chitosan chloride (TMC), was used to form complexes with the plasmid DNA encoding VEGF. The complexes were then incorporated into the collagen scaffold, the loading being mediated by the feeding concentration and release in a sustained manner. In vitro cell culture demonstrated a significant improvement in the VEGF expression level from the TMC/DNA complexes containing scaffolds, in particular with a large amount of DNA. The scaffolds containing the TMC/DNA complexes were subcutaneously implanted into Sprague-Dawley mice to study their angiogenesis via macroscopic observation, hematoxylin-eosin staining and immunohistochemical staining. The results demonstrated that the incorporation of TMC/DNA complexes could effectively enhance the in vivo VEGF expression and thereby the angiogenesis of implanted scaffolds.
PMID: 19406694 [found with GoPubMed]
25: Biotechnol J 2009 Apr;
Ex vivo expansion of adipose tissue-derived stem cells in spinner flasks
Zhu, Y, Liu, T, Song, K, Fan, X, Ma, X, Cui, Z, Dalian R&D Center for Stem Cell and Tissue Engineering, Dalian University of Technology, Dalian, China
Recent reports indicate that adipose tissue is a novel source of multipotent stem cells that can be used in cell therapy and tissue engineering. However, using the traditional cultivation of adipose tissue-derived stem cells (ADSCs), it is hard to meet the needs of clinical applications. To obtain a large number of ADSCs while retaining their stemness, we seeded ADSCs in collagen/chitosan scaffolds and compared the proliferation of ADSCs in a 3-D static environment in dishes and a 3-D dynamic environment in spinner flask. The growth dynamic parameters of ADSCs were examined using a CCK-8 kit every other day, and the variations of glucose and lactic acid concentrations were analyzed every day. After 14 days, the cells were observed under a scanning electron microscope. The surface markers (CD29, CD34, CD44, CD45, CD73, CD105, CD166 and HLA-DR), the specific transcription factors (Nanog, Oct-4, Sox-2 and Rex-1) and the multi-differentiation potential (adipogenic, osteogenic and chondrogenic) were also assayed to identify the stemness of expanded cells. The results showed that the cells in scaffolds in spinner flask could be expanded by more than 26 times, and they presented better morphology and vitality and stronger differentiation ability than the cells cultivated in scaffolds statically. All the cells maintained stem cell characteristics after proliferation. Therefore, spinner flask cultivation is an easy-to-use, inexpensive system for expanding ADSCs in 3-D scaffolds.
PMID: 19404993 [found with GoPubMed]
26: Biotechnol Lett 2009 Apr;
Improvement of chloroperoxidase stability by covalent immobilization on chitosan membranes
Zhang, L H, Bai, C H, Wang, Y S, Jiang, Y C, Hu, M C, Li, S N, Zhai, Q G, School of Chemistry and Materials Science, Shaanxi Normal University, Chang'an South Road, 199, Xi'an, Shaanxi, 710062, People's Republic of China
Chloroperoxidase (CPO) from Caldariomyces fumago was optimally covalently immobilized on chitosan membranes pretreated with 0.8 M glutaraldehyde at pH 3.5 to give 3.18 mg CPO g(-1) support. Using monochlorodimedone (MCD) as assay substrate, the immobilized-CPO retained 40% activity at 50 degrees C after 40 min whereas free CPO retained only 0.02%. The residual activity for immobilized-CPO was 99 and 58% compared with 68 and 43% for free CPO in the presence of 1.5 M urea and 300 muM H(2)O(2), respectively, after 20 h.
PMID: 19404743 [found with GoPubMed]
27: J Biomed Mater Res B Appl Biomater 2009 Apr;
Dynamic compression modulates chondrocyte proliferation and matrix biosynthesis in chitosan/gelatin scaffolds
Wang, P Y, Chow, H H, Lai, J Y, Liu, H L, Tsai, W B, Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan
It is well-documented that dynamical compression stimulates biosynthesis of extracellular biomacromolecules in cartilage explant or in chondrocyte/hydrogel systems. The object of this study was to apply high-strain dynamic compression to cell-seeded elastic scaffolds for articular cartilage tissue engineering. Rabbit chondrocytes had been cultured in chitosan/gelatin scaffolds for 3 days before dynamic compression. The chondrocyte/scaffold constructs were subjected to short-term (3 or 9 h) or long-term (6 h/day for 3 weeks) cyclic compression with 40% strain and 0.1 Hz. The expression of type II collagen and aggrecan was upregulated after 3-h of compression when compared with the free-swelling samples. Furthermore, long-term culture under dynamic compression facilitated cellular proliferation and deposition of glycosaminoglycan. Our results suggest that high-strain dynamic compression combined with elastic scaffolds might benefit articular cartilage tissue engineering. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009.
PMID: 19399846 [found with GoPubMed]
28: J Biomed Mater Res B Appl Biomater 2009 Apr;
Use of chitosan membrane associated with polypropylene mesh to prevent peritoneal adhesion in rats
Paulo, N M, de Brito E Silva, M S, Moraes, A M, Rodrigues, A P, de Menezes, L B, Miguel, M P, de Lima, F G, de Morais Faria, A, Lima, L M, Department of Veterinary Medicine, School of Veterinary Medicine, Federal University of Goiás, CEP 74001-970 Goiânia, Goiás, Brazil
The correction of wall abdominal defects often requires the use of implants such as polypropylene meshes. In spite of presenting good tissue acceptance, these biomaterials can migrate to adjacent viscera, promote enterocutaneos fistulas, tissue adherence and visceral erosions. In this work, the barrier effect of chitosan films associated with polypropylene meshes on adhesion formation experimentally induced in Wistar rats was evaluated. The animals were divided into two groups with 10 animals each. Animals in the CPP group were implanted with chitosan films associated with polypropylene meshes, whereas the ones in the PP group received only polypropylene meshes. After 8 days, the animals were submitted to euthanasia using CO(2) and a descriptive study focusing adhesion formation, visceral involvement with sutures and mesh peritonization was performed. Also, subimplanted material was collected for histopathology analysis. The results showed that the CPP group presented weak adhesions to the omentum over the stitch knots in eight animals. In all animals, the meshes were peritonized, not allowing their visualization after removing the chitosan films. In the PP group, six animals presented intestinal adhesions to the meshes and, in one of them, hepatic adhesion to the mesh was observed, besides omentum adhesion on more than 50% of the mesh area. The protective effect of chitosan films when sutured over polypropylene meshes, as well as no exacerbation of inflammation associated to the peritoneal lesions was statistically demonstrated. Therefore, chitosan films can indeed minimize the formation of peritoneal adhesions induced by polypropylene meshes in rats. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009.
PMID: 19399842 [found with GoPubMed]
29: J Huazhong Univ Sci Technolog Med Sci 2009 Apr;29(2):239-42
Chitosan/pshRNA plasmid nanoparticles targeting MDR1 gene reverse paclitaxel resistance in ovarian cancer cells
Yang, Yan, Wang, Zehua, Li, Minfang, Lu, Shi, Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparticles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDR1-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope (TEM). MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration (IC50) of paclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control (P<0.05). MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC50 (0.197+/-0.003, 0.144+/-0.001, 0.120+/-0.004) were decreased with difference being significant when compared with that in A2780/TS (0.269+/-0.003) cells control (P<0.05). It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.
PMID: 19399413 [found with GoPubMed]
30: Mol Biosyst 2009 Apr;5(4):391-6
Chitosan: a novel platform in proton-driven DNA strand rearrangement actuation
Lee, Dami, Singha, Kaushik, Jang, Mi-Kyeong, Nah, Jae-Woon, Park, In-Kyu, Kim, Won Jong, Department of Chemistry, The Brain Korea 21 Project, Polymer Research Institute, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 790-784, Korea
Nanometre-scaled DNA machine based on molecular recognition properties of DNA has now become a powerful tool in nanodevices, miniaturized structure, and nanofabrication. The common principle behind designing a DNA nanomachine is DNA strand exchange or rearrangement, which is solely controlled by the stabilization through associative and dissociative forces arising from base pair interaction of DNA molecules. Thus, highly effective DNA reaction actuator will make DNA nanomachine more flexible, controllable, and powerful device. Here, we report the novel polymer-mediated platform in proton-driven DNA strand rearrangement actuation. This cationic low molecular weight water-soluble chitosan (LMWSC) exhibited pH-dependent complexation with oligodeoxynucleotides (ODN). It formed complex with ODN only at low pH and accelerated the DNA strand exchange (or rearrangement) reaction between dsDNA and its complementary ssDNA at pH 5.0. However, no complexation was observed between LMWSC and ODN at neutral pH. We assume that at physiological pH, LMWSC is not protonated enough for formation of complex with ODN. Therefore, it can not diminish the electrostatic repulsion among the negatively charged DNA strands of the three-stranded intermediate formed during the strand exchange reaction. In contrast, LMWSC becomes positively charged at acidic pH, and it stabilizes the three-stranded intermediate by spreading out the accumulated counter-ions and increasing the entropy of the system. This fascinating observation prompted us to believe that this intelligent proton-driven DNA reaction actuator has a potential for the precise control of DNA nanomachine and would be applied for operating and controlling nanoscaled machine.
PMID: 19396376 [found with GoPubMed]
31: Can J Microbiol 2009 Apr;55(4):347-55
Inhibition of Listeria monocytogenes by a combination of chitosan and divergicin M35
Benabbou, R, Zihler, A, Desbiens, M, Kheadr, E, Subirade, M, Fliss, I, Institut des Nutraceutiques et des aliments fonctionnels, Universite Laval, QC G1K 7P4, Canada
The antimicrobial activities of the class IIa bacteriocin divergicin M35 and several types of chitosan against Listeria monocytogenes were quantified by agar diffusion, critical micro-dilution, and viable count and observed by electron microscopy. Antimicrobial activity of chitosan depended on its molecular mass (MM) and the pH. Three chitosans with MM values of 2, 20, and 100 kDa and 87.4% degree of deacetylation (DDA) were chosen for further study, based on high anti-listerial activity at pH 4.5. Electron microscopy suggested that the mechanism of anti-listerial activity also varied with the MM. Low-MM chitosan appeared to inhibit L. monocytogenes by affecting cell permeability and growth, whereas medium- and high-MM chitosan may form a barrier on the cell surface that prevents entry of nutrients. The minimum inhibitory concentrations (MICs) of 2, 20, and 100 kDa chitosan and divergicin M35 against a divergicin-resistant strain of L. monocytogenes (LSD 535) were 2.5, 2.5, 0.625, and 0.25 mg/mL, respectively. The combination of any of these 3 chitosans and divergicin M35 appeared to have an additive effect against L. monocytogenes, as determined by fractional inhibitory concentration (FIC) index. This study provides useful data for the development of chitosan films incorporating divergicin M35 for inhibiting L. monocytogenes in foods.
PMID: 19396234 [found with GoPubMed]
32: Acta Biomater 2009 Apr;
Self-assembly of a swollen chitosan/chondroitin sulfate hydrogel by outward diffusion of the chondroitin sulfate chains
Piai, J F, Rubira, A F, Muniz, E C, Grupo de Materiais Poliméricos e Compósitos, GMPC, Departamento de Química, Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900 Maringá, Paraná, Brazil
A hydrogel constituted of chitosan (CT) and chondroitin sulfate (CS) was synthesized. In previously reported works the stochiometric ratio has been used, but in this paper an excess of CS (40% CT and 60% CS) was used because the hydrogel could be applied as a CS carrier. The hydrogel properties were investigated by differential scanning calorimetry, wide-angle X-ray scattering (WAXS), scanning electron microscopy, and high-performance liquid chromatography. Changes in the pH of the gel-surrounding liquid had a considerable effect on both the release and the molecular reorganization of CS. Furthermore, the formed hydrogel exhibited interesting parameters for use in biotechnology, such as water affinity, thermal properties and morphology upon sequential pH variation. The protonation or deprotonation of the different groups that participate in the complex formation and the coiling or uncoiling of like or unlike chains concomitant to the release of CS are believed to be the main factors affecting the hydrogel properties. CS was released mainly at pH higher than 6.5, the value of pK(aCT), and the released CS maximum fraction was approximately 0.5. The WAXS data demonstrated that the CT/CS complex in the hydrogel presented macromolecular reorganization at pHs ranging from 6 to 12.
PMID: 19394902 [found with GoPubMed]
33: Int J Hyperthermia 2009 Apr;:1-9
Preparation of carboplatin-Fe@C-loaded chitosan nanoparticles and study on hyperthermia combined with pharmacotherapy for liver cancer
Li, F R, Yan, W H, Guo, Y H, Qi, H, Zhou, H X, Clinical Medical Research Center, Second Clinical Medical College (Shenzhen People's Hospital), Jinan University, Shenzhen, China
Background: Magnetic fluid hyperthermia is a kind of technology for treating tumors based on nanotechnology. It is suitable to various types of tumors. The purpose of this study was to prepare carboplatin-Fe@C-loaded chitosan nanoparticles with Fe@C as a magnetic core and to investigate efficacy of hyperthermia combined with chemotherapy for transplanted liver cancer in rats. Methods: Fe@C nanopowder was treated with dilute hydrochloric acid to prepare Fe@C nanocage. Carboplatin-Fe@C-loaded chitosan nanoparticles were prepared by reverse microemulsion method with the nanocages as the magnetic cores, chitosan as the matrix. The shape, size, drug-loading rate, and in vitro cumulative release of the nanoparticles were observed and heat product under high frequency alternating electromagnetic field in vitro was explored. Eighty rats with transplanted liver cancer were randomly divided into 4 groups (group A: control group, group B: free carboplatin group, group C: nanoparticles with static magnetic field group, and group D: nanoparticles with static field and alternating magnetic field). Drug was injected into the hepatic artery. The therapeutic effect of hyperthermia combined with chemotherapy for tumor, toxicity and rat survival time were observed. Results: Carboplatin-Fe@C-loaded chitosan nanoparticles were spherical in shape with an average size of (207 +/- 21) nm and high saturation magnetization. The drug-loading rate of the nanoparticles was 11.0 +/- 1.1%. The cumulative release percentage of carboplatin-Fe@C-loaded chitosan nanoparticles in vitro at different point time phase of 24 h, 48 h, 72 h, 96 h and 120 h were 51%, 68%, 80%, 87% and 91%, respectively. With an increase in carboplatin-Fe@C-loaded chitosan nanoparticle concentration and magnetic field strength, the heating rate and constant temperature of carboplatin-Fe@C-loaded chitosan nanoparticles dispersed in physiological saline were increased in an alternating magnetic field. In vivo experiments showed that after particle injection, tumor temperature reached 42.6 degrees +/- 0.2 degrees C within 10 min in the alternating magnetic field; and the temperatures in the right hepatic lobes and the rectum were significantly lower than in the tumor and the constant temperature could last up to 30 min. The inhibition ratio of tumor weight in group D was significantly enhanced, no obviously toxic and side-effect occurred and survival time was prolonged. Conclusion: Carboplatin-Fe@C-loaded chitosan nanoparticles possess good magnetic targeting and heat production properties. They can target liver cancer tissue by static magnetic field, and with the application of alternating magnetic field, effectively raise tumor tissue temperature and facilitate tumor apoptosis. The combination of chemotherapy and magnetic materials into nanoparticles as described herein demonstrates promising efficacy.
PMID: 19391033 [found with GoPubMed]
34: Tissue Eng Part A 2009 Apr;
A novel scaffold with longitudinally oriented micro-channels promotes peripheral nerve regeneration
Hu, X, Huang, J, Ye, Z, Xia, L, Li, M, Lv, B, Shen, X, Luo, Z, Institute of Orthopaedics, Xijing Hospital, the Fourth Military Medical University, Xi'an, China;
Longitudinally oriented micro-structures are essential for a nerve scaffold to promote significant regeneration of injured peripheral axons across nerve gaps. Extensive attention has been devoted to develop scaffolds with inner structures mimicking the nerve-guiding basal lamina micro-channels in autografts. However, to date, little information has been obtained about scaffolds with similar inner microstructures, and the efficacy of such scaffolds in bridging peripheral nerve gaps in vivo has never been examined. In the present study, we describe a novel nerve-guiding collagen-chitosan (CCH) scaffold with inner dimensions resembling the basal lamina micro-channels of normal nerves. The scaffold has a number of structural advantages including longitudinally orientated micro-channels through its entire length and extensive interconnected pores between the parallel micro-channels. We evaluated the efficacy of the CCH scaffold to bridge a 15 mm long sciatic nerve defect in rats using a combination of morphological and functional techniques. The in vivo animal study showed that the CCH scaffold achieved nerve regeneration and functional recovery equivalent to that of an autograft, without the exogenous delivery of regenerative agents or cell transplantation. These findings demonstrate that CCH scaffolds may be used as alternatives to nerve autografts for peripheral nerve regeneration.
PMID: 19382873 [found with GoPubMed]
35: J Tissue Eng Regen Med 2009 Apr;
Comparative chondrogenesis of human cell sources in 3D scaffolds
Seda Tigli, R, Ghosh, S, Laha, M M, Shevde, N K, Daheron, L, Gimble, J, Gümüsderelioglu, M, Kaplan, D L, Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
Cartilage tissue can be engineered by starting from a diversity of cell sources, including stem-cell based and primary cell-based platforms. Selecting an appropriate cell source for the process of cartilage tissue engineering or repair is critical and challenging, due to the variety of cell options available. In this study, cellular responses of isolated human chondrocytes, human embryonic stem cells and mesenchymal stem cells (MSCs) derived from three sources, human embryonic stem cells, bone marrow and adipose tissue, were assessed for chondrogenic potential in 3D culture. All cell sources were characterized by FACS analysis to compare expression of some surface markers. The cells were differentiated in two different biomaterial matrices, silk and chitosan scaffolds, in the presence and absence of bone morphogenetic protein 6 (BMP6), along with the standard chondrogenic differentiating factors. Embryonic stem cells-derived MSCs showed unique characteristics, with preserved chondrogenic phenotype in both scaffolds with regard to chondrogenesis, as determined by real time RT-PCR, histological and microscopical analyses. After 4 weeks of cultivation, embryonic stem cells-derived MSCs were promising for chondrogenesis, particularly in the silk scaffolds with BMP6. The results suggest that cell source differences are important to consider with regard to chondrogenic outcomes, and among the variables addressed here the human embryonic stem cells-derived MSCs were the preferred cell source. Copyright (c) 2009 John Wiley & Sons, Ltd.
PMID: 19382119 [found with GoPubMed]
36: Drug Dev Ind Pharm 2009 Apr;:1-11
Influence of the preparation procedure and chitosan type on physicochemical properties and release behavior of alginate-chitosan microparticles
Cekic, N D, Milic, J R, Savic, S D, Savic, M M, Jovic, Z, Daniels, R, DCP Hemigal, Leskovac, Serbia
Background: The potential for use of chitosan-treated alginate microparticles as a vehicle for oral phenytoin delivery has not been thoroughly exploited. Aim: We studied the influence of preparation procedure and chitosan type on physicochemical properties and release behavior of alginate-chitosan microparticles. Method: The total number of 24 microparticles formulations prepared by varying contents of calcium gelling ions and varying contents and type of chitosan was examined. As an additional variable, two different hardening times (1 and 24 hours) were employed. Possible interactions of components, surface morphology of microparticles as well as release profile of phenytoin were studied. Results: Both series of formulations with regard to hardening times, irrespective of the chitosan type and/or concentration employed appeared to be highly loaded with the model drug (above 90%). The drug release studies showed that the kinetics of phenytoin cannot be straightforwardly predicted based on the molecular weight of chitosan alone. On the other hand, prolonging the hardening time from 1 to 24 hours had significantly improved phenytoin kinetics, and gave rise to a formulation with the liberation half-time of about 2.5 hours. Conclusion: This study showed that the latter formulation is eligible for further modifications aimed at improving the regularity of phenytoin absorption.
PMID: 19365778 [found with GoPubMed]
37: Drug Dev Ind Pharm 2009 Apr;:1-6
Chitosan-glycolic acid: a possible matrix for progesterone delivery into skin
Kahlig, H, Hasanovic, A, Biruss, B, Holler, S, Grim, J, Valenta, C, Institute of Organic Chemistry, University of Vienna, Vienna, Austria
Background: Chitosan-EDTA is an interesting matrix for dermal delivery; however, the adhesiveness is too small. Therefore, the purpose of this study was to investigate chitosan-glycolic acid as possible dermal matrix for progesterone in comparison to chitosan-EDTA and carrageenan. Method: After preparation of the chitosan-glycolic acid salt and characterization by NMR and FTIR, tensile studies using porcine skin and rheology measurements as well as standard diffusion experiments using dermatomed porcine skin were performed. Results: Results showed an improved skin adhesiveness of chitosan-glycolic acid and increased viscosity. Skin diffusion studies indicated the highest cumulative permeation of progesterone after 48 hours from chitosan-glycolic acid followed by carrageenan and chitosan-EDTA. A possible explanation might be a longer residence time on skin caused by the higher adhesiveness and with it higher progesterone skin permeation. Conclusion: Chitosan-glycolic acid can be recommended as a suitable polymer for hydrogels and an adhesive matrix for a transdermal application of progesterone exhibiting excellent skin adhesiveness and permeation properties.
PMID: 19365777 [found with GoPubMed]
38: Arch Ophthalmol 2009 Apr;127(4):525-32
Effect of chitosan-N-acetylcysteine conjugate in a mouse model of botulinum toxin B-induced dry eye
Hongyok, Teeravee, Chae, Jemin J, Shin, Young Joo, Na, Daero, Li, Li, Chuck, Roy S, Wilmer Ophthalmological Institute, Johns Hopkins University, Baltimore, Maryland 21287, USA
OBJECTIVE: To evaluate the effect of a thiolated polymer lubricant, chitosan-N-acetylcysteine conjugate (C-NAC), in a mouse model of dry eye. METHODS: Eye drops containing 0.5% C-NAC, 0.3% C-NAC, a vehicle (control group), artificial tears, or fluorometholone were applied in a masked fashion in a mouse model of induced dry eye from 3 days to 4 weeks after botulinum toxin B injection. Corneal fluorescein staining was periodically recorded. Real-time reverse transcriptase-polymerase chain reaction and immunofluorescence staining were performed at the end of the study to evaluate inflammatory cytokine expressions. RESULTS: Mice treated with C-NAC, 0.5%, and fluorometholone showed a downward trend that was not statistically significant in corneal staining compared with the other groups. Chitosan-NAC formulations, fluorometholone, and artificial tears significantly decreased IL-1beta (interleukin 1beta), IL-10, IL-12alpha, and tumor necrosis factor alpha expression in ocular surface tissues. CONCLUSIONS: The botulinum toxin B-induced dry eye mouse model is potentially useful in evaluating new dry eye treatment. Evaluation of important molecular biomarkers suggests that C-NAC may impart some protective ocular surface properties. However, clinical data did not indicate statistically significant improvement of tear production and corneal staining in any of the groups tested. CLINICAL RELEVANCE: Topically applied C-NAC might protect the ocular surface in dry eye syndrome, as evidenced by decreased inflammatory cytokine expression.
PMID: 19365035 [found with GoPubMed]
39: Tissue Eng Part C Methods 2009 Apr;
Effect of chitosan as a dispersant on collagen-hydroxyapatite composite matrices
Zhang, L, Tang, P, Zhang, W, Xu, M, Wang, Y, Chinese PLA General Hospital, Department of Orthopaedics, Beijing, China;
Purpose: HA powder is difficult to disperse evenly in collagen gelatum, which can affect the properties of the final collagen-hydroxyapatite composite. Here, we used chitosan (CS) as a dispersant in a bone matrix constructed with collagen (Col) and Ca5(PO4)3OH (hydroxyapatite/HA), which are the main components of natural bone. Solid-liquid phase separation was used to shape a 3D porous structure to support cell growth. Methods: The two bone matrices (Col-CS-HA and Col-HA) were investigated by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Electron Spectroscopy for Chemical Analysis (ESCA) for structural characteristics and physico-chemical properties. Their ability to repair bone defects was evaluated in vivo. Results: HA particles were dispersed in Col gelatum evenly by mixing with CS gelatum. The surface morphology and 3D structure of the matrix became more regular, which improved cell growth. After CS modification, the percentage of C-N groups increased to 6.40% and C-OH groups increased from 1.05% to 6.92%. The total amount of non-polar groups (C-C groups and C-H groups) decreased from 82.48% to 74.05%. The vitrification and denaturation temperatures increased from 40.59 C and 106.36 C, respectively, to 42.23 C and 111.04 C, respectively. Conclusion: CS modified the surface chemistry to create a favorable environment for osteoblast adhesion and proliferation in vivo, which would accelerate the process of bone regeneration. The Col-CS-HA matrix possessed superior biological and mechanical properties for bone defect repair.
PMID: 19364274 [found with GoPubMed]
40: Mini Rev Med Chem 2009 Apr;9(4):463-9
Chitosan micro- and nanospheres: fabrication and applications for drug and DNA delivery
Masotti, Andrea, Ortaggi, Giancarlo, Chemistry Department, SAPIENZA University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
Polysaccharides and other cationic polymers have been recently used in pharmaceutical research and industry for their properties to control the release of antibiotics, DNA, proteins, peptide drugs or vaccines. They have been also extensively studied as non viral DNA carriers for gene delivery and therapy. Chitosan is one of the most used since it can promote long-term release of incorporated drugs. Here, we reviewed the recent literature on the preparation of chitosan micro- and nanospheres using different manufacturing processes (nanofabrication). Moreover, the preparation of chitosan and chitosan/DNA nanospheres using a novel and simple osmosis-based method has been recently reported. This novel nanofabrication method may be a useful alternative to obtain small DNA-containing nanospheres (38+/-4 nm) for biomedical applications. The reported method has general applicability to various synthetic or natural biopolymers. Solvent, temperature and membrane cut-off are the physicochemical parameters able to control the overall osmotic process leading to obtain several nanostructured systems with different size and shape that may be used in several biotechnological applications.
PMID: 19356124 [found with GoPubMed]
41: Biomed Chromatogr 2009 Apr;
Validation of a high-performance liquid chromatography method for the determination of (-)-alpha-bisabolol from particulate systems
Pedro, A S, Detoni, C, Ferreira, D, Cabral-Albuquerque, E, Sarmento, B, Medical Subject Research Laboratory, Faculty of Pharmacy, Federal University of Bahia, Brazil
A reversed-phase high performance liquid chromatography method has been developed and validated for determination and quantitation of the natural sesquiterpene (-)-alpha-bisabolol. Furthermore the application of the method was done by characterization of chitosan milispheres and liposomes entrapping Zanthoxylum tingoassuiba essential oil, which contains appreciable amount of (-)-alpha-bisabolol. A reversed-phase C(18) column and gradient elution was used with the mobile phase composed of (A) acetonitrile-water-phosphoric acid (19:80:1) and (B) acetonitrile. The eluent was pumped at a flow rate of 0.8 mL/min with UV detection at 200 nm. In the range 0.02-0.64 mg/mL the assay showed good linearity (R(2 )= 0.9999) and specificity for successful identification and quantitation of (-)-alpha-bisabolol in the essential oil without interfering peaks. The method also showed good reproducibility, demonstrating inter-day and intra-day precision based on relative standard deviation values (up to 3.03%), accuracy (mean recovery of 100.69% +/- 1.05%) and low values of detection and quantitation limits (0.0005 and 0.0016 mg/mL, respectively). The method was also robust for showing a recovery of 98.81% under a change of solvent in standard solutions. The suitability of the method was demonstrated by the successful determination of association efficiency of the (-)-alpha-bisabolol in chitosan milispheres and liposomes. Copyright (c) 2009 John Wiley & Sons, Ltd.
PMID: 19353738 [found with GoPubMed]
42: J Biomed Mater Res A 2009 Apr;
Design and characterization of a biodegradable composite scaffold for ligament tissue engineering
Hayami, J W, Surrao, D C, Waldman, S D, Amsden, B G, Department of Chemical Engineering, Queen's University, Kingston, Canada
Herein we report on the development and characterization of a biodegradable composite scaffold for ligament tissue engineering based on the fundamental morphological features of the native ligament. An aligned fibrous component was used to mimic the fibrous collagen network and a hydrogel component to mimic the proteoglycan-water matrix of the ligament. The composite scaffold was constructed from cell-adherent, base-etched, electrospun poly(epsilon-caprolactone-co-D,L-lactide) (PCLDLLA) fibers embedded in a noncell-adherent photocrosslinked N-methacrylated glycol chitosan (MGC) hydrogel seeded with primary ligament fibroblasts. Base etching improved cellular adhesion to the PCLDLLA material. Cells within the MGC hydrogel remained viable (72 +/- 4%) during the 4-week culture period. Immunohistochemistry staining revealed ligament ECM markers collagen type I, collagen type III, and decorin organizing and accumulating along the PCLDLLA fibers within the composite scaffolds. On the basis of these results, it was determined that the composite scaffold design was a viable alternative to the current approaches used for ligament tissue engineering and merits further study. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2009.
PMID: 19353565 [found with GoPubMed]
43: J Biomed Mater Res A 2009 Apr;
Effect of surface wettability and charge on protein adsorption onto implantable alginate-chitosan-alginate microcapsule surfaces
Xie, H G, Li, X X, Lv, G J, Xie, W Y, Zhu, J, Luxbacher, T, Ma, R, Ma, X J, Laboratory of Biomedical Material Engineering, Biotechnology Division, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
Alginate-chitosan-alginate (ACA) microcapsules have been developed as a device for the transplantation of living cells. However, protein adsorption onto the surface of microcapsules immediately upon their implantation decides their ultimate biocompatibility. In this work, the chemical composition of the ACA membranes was determined using X-ray photoelectron spectroscopy (XPS). The surface wettability and charge were determined by contact angle and zeta potential measurements, respectively. Then, the effects of surface wettability and charge on bovine fibrinogen (Fgn) and gamma globulin (IgG) adsorption onto ACA microcapsules were evaluated. The results showed that ACA microcapsules had a hydrophilic membrane. So, the surface wettability of ACA microcapsules had little effect on protein adsorption. There was a negative zeta potential of ACA microcapsules which varies with the viscosity or G content of alginate used, indicating a varying degree of net negatively charged groups on the surface of ACA microcapsules. The amount of adsorbed protein increased with increasing of positive charge. Furthermore, the interaction between proteins and ACA microcapsules is dominated by electrostatic repulsion at pH 7.4 and that is of electrostatic attraction at pH 6.0. This work could help to explain the bioincompatibility of ACA microcapsules and will play an important role in the optimization of the microcapsule design. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2009.
PMID: 19353563 [found with GoPubMed]
44: Biophys J 2009 Apr;96(7):2719-26
Electroformation of giant vesicles from an inverse phase precursor
Mertins, Omar, da Silveira, Nádya P, Pohlmann, Adriana R, Schröder, André P, Marques, Carlos M, Institut Charles Sadron, UPR22, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
We discuss a simple modification of the well-known method of giant vesicle electroformation that allows for a direct addition of water-soluble species to the phospholipid bilayers. Using this modified method, we prepare phospholipid vesicles decorated with chitosan, a water-soluble polysaccharide currently investigated for potential pharmacological applications. We find that the method allows this polysaccharide with primary amino groups on every glucose subunit to be tightly bound to the membrane, rather than simply being encapsulated.
PMID: 19348754 [found with GoPubMed]
45: J Am Chem Soc 2009 Apr;131(16):5748-50
Surpassing the use of copper in the click functionalization of polymeric nanostructures: a strain-promoted approach
Lallana, Enrique, Fernandez-Megia, Eduardo, Riguera, Ricardo, Departamento de Química Orgánica, Facultad de Química, and Unidad de RMN de Biomoléculas Asociada al CSIC, Universidad de Santiago de Compostela, AVda. de las Ciencias S.N., 15782 Santiago de Compostela, Spain
The limitations (depolymerization and Cu contamination) in the use of Cu(I)-catalyzed azide-alkyne [3 + 2] cycloadditions (CuAAC) for the selective click functionalization of polysaccharide-based systems have been efficiently surpassed using a strain-promoted approach (SPAAC). The SPAAC decoration of chitosan-g-poly(ethylene glycol) nanostructures with an immunoglobulin G under physiological conditions represents a step forward in the preparation of immunonanoparticles.
PMID: 19348483 [found with GoPubMed]
46: J Mater Sci Mater Med 2009 Apr;
Development of in situ-forming hydrogels for hemorrhage control
Peng, H T, Shek, P N, Defence Research and Development Canada - Toronto, 1133 Sheppard Avenue West, Toronto, ON, M3M 3B9, Canada,
We report the preparation of in situ-forming hydrogels, composed of oxidized dextran (Odex) and amine-containing polymers, for their potential use as a wound dressing to promote blood clotting. Dextran was oxidized by sodium periodate to introduce aldehyde groups to form hydrogels, upon mixing in solution with different polymers containing primary amine groups, including polyallylamine (PAA), oligochitosan and glycol chitosan. A series of experiments were conducted to identify the optimum gelation condition for the Odex-PAA system. The polymer concentration appeared to have a major effect on gelation time and the polymer weight ratio affected the resulting gel content and swelling. Other influencing factors included pH of the buffer used to dissolve each polymer, PAA molecular weight, and the type of individual material. The latter also contributed significantly to gel content and swelling. Thromboelastography was used to examine the effects of the in situ gelation on blood coagulation in vitro, where the Odex-PAA combination was found to be most pro-hemostatic, as indicated by a decrease in clotting time and an increase in clot strength. The results of this study demonstrated that in situ-forming hydrogels could promote clotting in vitro; however, further studies are required to determine if the same hydrogel formulations are effective in controlling hemorrhage in vivo.
PMID: 19347258 [found with GoPubMed]
47: Anal Chim Acta 2009 Apr;639(1-2):51-6
Synthesis of novel chitosan resin possessing histidine moiety and its application to the determination of trace silver by ICP-AES coupled with triplet automated-pretreatment system
Hosoba, Minako, Oshita, Koji, Katarina, Rosi K, Takayanagi, Toshio, Oshima, Mitsuko, Motomizu, Shoji, Graduate School of Natural Science and Technology & Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan
A novel chitosan resin, cross-linked chitosan functionalized with histidine moiety (histidine-type chitosan resin), was synthesized for the collection and concentration of trace silver in aquatic samples. A triplet automated-pretreatment system (Triplet Auto-Pret System) installed mini-columns packed with the synthesized histidine-type chitosan resin was coupled with an inductively coupled plasma-atomic emission spectrometry (ICP-AES) for a rapid and sensitive analysis. Adsorption behavior of 50 elements on the histidine-type chitosan resin was examined. A trace amount of Ag(I) was shown a good adsorption in wide pH regions (pH 5-9), and Ag(I) adsorbed was readily recovered with 1 M nitric acid solution. The limit of detection (3sigma) for silver was 0.03 microg L(-1). The system was successfully applied to river water and dipped water in silver coated container.
PMID: 19345757 [found with GoPubMed]
48: J Phys Chem B 2009 Apr;113(17):5823-8
Unique rheological behavior of chitosan-modified nanoclay at highly hydrated state
Liang, Songmiao, Liu, Linshu, Huang, Qingrong, Yam, Kit L, Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901, USA
This work attempts to explore the dynamic and steady-state rheological properties of chitosan modified clay (CMCs) at highly hydrated state. CMCs with different initial chitosan/clay weight ratios (s) were prepared from pre-exfoliated clay via electrostatic adsorption process. Thermogravimetric analysis and optical microscopy were used to determine the adsorbed content of chitosan (m) in CMCs and the microstructure of CMCs at highly hydrated state, respectively. Dynamic rheological results indicate that both stress-strain behavior and moduli of CMCs exhibit strong dependence on m. Shear-thinning behavior for all of CMCs is observed and further confirmed by steady-state shear test. Interestingly, two unique transitions, denoted as a small peak region of the shear viscosity for CMCs with m > 2.1% and a sharp drop region of the shear viscosity for CMCs with m <or= 6.3%, were observed at shear rate range of about 10 < gamma < 40 and 0.2 < gamma < 0.5 s(- 1), respectively. Further, analysis on the recovery of CMCs at rest after underwent a preshearing process was performed with an emphasis to explain the presence of these unique transitions. Thixotropic effect was observed in CMCs and showed strong dependence on m and the preshearing history. Failure to Cox-Merz rule of the rheological behavior of CMCs suggests that some preferential orientation of the initial quiescent random arrangement of CMCs particles or their tactoids occurs under the applied shearing.
PMID: 19344170 [found with GoPubMed]
49: Int J Pharm 2009 Apr;371(1-2):134-41
Chitosan-dibasic orthophosphate hydrogel: a potential drug delivery system
Ta, Hang T, Han, Han, Larson, Ian, Dass, Crispin R, Dunstan, Dave E, Department of Chemical and Biomolecular Engineering, University of Melbourne, Vic. 3010, Australia
Injectable thermo-activated hydrogels have shown great potential in biomedical applications including use in therapeutic delivery vehicles. In addition to their biocompatibility, the feasibility of these delivery systems is significantly contributed by their ability to gel at physiological conditions and to release entrapped molecules in a sustained manner. In this study, parameters affecting the gelling behavior and the release characteristics of a neutral hydrogel system based on chitosan and an inorganic orthophosphate salt have been investigated. Monobasic and tribasic phosphate salts were not effective in inducing gelation of chitosan solution. However, in the presence of dibasic phosphate salt such as dipotassium hydrogen orthophosphate (DHO), the acidic chitosan solution was neutralized and gelling at temperature and time regulated by varying chitosan and salt concentrations in the formulation. The release rate of the entrapped macromolecules depended on chitosan concentration, DHO concentration, structural conformation and molecular weight of entrapped agents. The relationship between the morphology of the hydrogel and the release profiles are discussed. Chitosan/DHO (Chi/DHO) hydrogels were found to be cytocompatible as evaluated in an in vitro study using a human cell line. These results indicate the potential of Chi/DHO hydrogels as delivery systems for different therapeutic agents with controlled release kinetics.
PMID: 19340925 [found with GoPubMed]
50: Macromol Biosci 2009 Apr;
Self Assembling and Crosslinking of Polyelectrolyte Multilayer Films of Chitosan and Alginate Studied by QCM and IR Spectroscopy
Alves, N M, Picart, C, Mano, J F, 3B's Research Group, Biomaterials, Biodegradables and Biomimetics, Dept. of Polymer Engineering, University of Minho, AvePark, Zona Industrial da Gandra, S. Cláudio do Barco, 4806-909 Caldas das Taipas, Guimarães, Portugal
The formation of novel biocompatible multilayer films based on the alternate deposition of CHI and ALG was investigated for the first time by QCM-D and FTIR-ATR. A linear increase of the thickness was found during the film build-up. GLUT was used to crosslink the films terminated with either CHI or ALG. A change in the QCM-D signal was observed just in the first case, indicating that crosslinking only takes place in the top CHI layer. The evolution of the dissipation factor during crosslinking was modelled with a first-order kinetics; this reaction was found to be faster for chitosan terminated films with a lower number of multilayers. It was also found that more robust films could be produced by crosslinking the intermediate CHI layers during the build-up.
PMID: 19340816 [found with GoPubMed]
51: Yakugaku Zasshi 2009 Apr;129(4):475-84
Evaluation of the binding affinity and RNA interference of low-molecular-weight chitosan/siRNA complexes using an imaging system
Kawaguchi, Yasuhisa, Okuda, Tomoyuki, Ban, Tatsunori, Danjo, Kazumi, Okamoto, Hirokazu, Faculty of Pharmacy, Meijo University, Japan
Chitosan is one of the attractive non-viral carriers for gene delivery including siRNA. However, common chitosan, which has a relatively high molecular weight, is insoluble in water, which might make it difficult to apply clinically. In this study, we investigated the efficacy of low-molecular-weight chitosan (LMWC), which is soluble in water, as a carrier for siRNA delivery. To evaluate the binding affinity and RNA interference (RNAi) of LMWC/siRNA complexes, a multi-well imaging system (IVIS) was adapted. CT26 cells stably expressing firefly luciferase (CT26/Luc cells) were established to evaluate RNAi. Evaluation of RNAi using lipofectamine(TM) 2000 was carried out by employing a luminometer with cell lysis and IVIS without cell lysis. The results were closely correlated, suggesting the advantages of the multi-well imaging system regarding screening, the visualization of results, and nondestructive evaluation. Fluorescence generated by ethidium bromide intercalated in the double strand of siRNA was markedly quenched at a higher ratio of LMWC to siRNA (N/P) and lower pH. Evaluation of the particle size and zeta potential of LMWC/siRNA complexes also indicated the higher binding affinity of LMWC with siRNA. At N/P=300 and pH 6.5, which satisfied the high-level binding affinity of LMWC with siRNA, significantly lower luminescence was detected in CT26/Luc cells treated with LMWC/siRNA compared with those treated with LMWC alone, suggesting the presence of RNAi. These results suggested that LMWC may be an effective carrier for siRNA delivery, and that the multi-well imaging system may be a powerful tool to evaluate the binding affinity and RNAi.
PMID: 19337002 [found with GoPubMed]
52: Biol Pharm Bull 2009 Apr;32(4):706-10
N/P ratio significantly influences the transfection efficiency and cytotoxicity of a polyethylenimine/chitosan/DNA complex
Zhao, Qing-Qing, Chen, Jin-Liang, Lv, Teng-Fei, He, Cai-Xia, Tang, Gu-Ping, Liang, Wen-Quan, Tabata, Yasuhiko, Gao, Jian-Qing, College of Pharmaceutical Sciences, Zhejiang University. PR China
For designing a complex vector that has the advantages of both polyethylenimine (PEI) and chitosan for gene delivery, a PEI/chitosan/DNA complex was constructed at various N/P ratios (the ratios of moles of the amine groups of cationic polymers to those of the phosphate ones of DNA) and both the cytotoxicity and the transfection efficiency of the vector were evaluated. The results demonstrated that the chitosan/DNA binding degree was depended on the N/P ratio. The mean size of the complex vector was between 100 nm and 150 nm. Compared with PEI/DNA, the complex vector (PEI/chitosan/DNA with chitosan/DNA N/P=4, PEI/DNA N/P=10) appeared to have low cytotoxicity, which maintained the cell survival rate at greater than 80%, and showed higher transfection efficiency of nearly 1000 fold compared with that using chitosan/DNA alone. Furthermore, the expression efficiency of the complex vector carrying enhanced green fluorescent protein was not inhibited in the presence of serum in both HeLa cells and A549 cells. The PEI/chitosan complex may be a promising gene carrier that has high transfection efficiency as well as low cytotoxicity.
PMID: 19336909 [found with GoPubMed]
53: J Control Release 2009 Apr;135(2):144-51
Synthesis and evaluation of lauryl succinyl chitosan particles towards oral insulin delivery and absorption
Rekha, M R, Sharma, Chandra P, Division of Biosurface Technology, Biomedical Technology Wing Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, India
In this work a novel chitosan derivative, lauryl succinyl chitosan (LSC) was developed for the purpose of evaluating its applications towards oral peptide delivery system. Nano/microparticles were developed from this derivative by sodium tripolyphosphate (TPP) cross linking. Human insulin was used as the model protein drug and the release kinetics was studied at gastrointestinal pH. The presence of succinyl carboxyl groups had inhibitory effect on the release kinetics of insulin at pH 1.2 minimizing up to about 8.5+/-0.45% in two hours. Results showed that the presence of hydrophobic moieties controlled the release of the loaded insulin from the particles at intestinal pH. The particles were negatively charged with size ranging from 315 nm to 1.090 microm. The mucoadhesive capacity was established ex vivo using the jejunum of rat intestine. Confocal microscopy studies proved the tight junction permeability in Caco 2 cells and in vivo uptake of the FITC-insulin from loaded nanoparticles by the rat intestinal epithelium. The results demonstrated that the modified chitosan with both hydrophilic (succinyl) and hydrophobic (lauryl) moieties had improved the release characteristics, mucoadhesivity as well as the permeability of the insulin compared to the native chitosan particles. The LSC2 particles were capable of reducing blood glucose levels in diabetic rats for the duration of about 6 h. This indicated that this novel derivative could be a promising candidate for oral peptide delivery.
PMID: 19331862 [found with GoPubMed]
54: Proteomics 2009 Apr;9(8):2149-62
Plasma proteome analysis for anti-obesity and anti-diabetic potentials of chitosan oligosaccharides in ob/ob mice
Kumar, Suresh G, Rahman, Md Atiar, Lee, Sung Hak, Hwang, Hee Sun, Kim, Hyun Ah, Yun, Jong Won, Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk, Republic of Korea
Altered levels of adipokines, derived as a result of distorted adipocytes, are the major factors responsible for changing biochemical parameters in obesity that leads to the development of metabolic disorders such as insulin resistance and atherosclerosis. In our previous reports, chitosan oligosaccharides (CO) were proved to inhibit the differentiation of 3T3-L1 adipocytes. In the present study, an attempt was made to investigate the anti-obesity and anti-diabetic effect of CO on ob/ob mice, by means of differential proteomic analysis of plasma. This was followed by immunoblotting, and gene expression in adipose tissue to clarify the molecular mechanism. CO treatment showed reduced diet intake (13%), body weight gain (12%), lipid (29%) and glucose levels (35%). 2-DE results showed differential levels of five proteins namely RBP4, apoE, and apoA-IV by >2-fold down-regulation and by >2-fold of apoA-I and glutathione peroxidase (GPx) up-regulation after CO treatment. Immunoblotting studies of adiponectin and resistin showed amelioration in their levels in plasma. Furthermore, the results of gene expressions for adipose tissue specific TNF-alpha, and IL-6 secretary molecules were also down-regulated by CO treatment. Gene expressions of PPAR gamma in adipose tissue were in good agreement with the ameliorated levels of adipokines, thereby improving the pathological state. Taken together, CO might act as a potent down-regulator of obesity-related gene expression in ob/ob mice that may normalize altered plasma proteins to overcome metabolic disorders of obesity.
PMID: 19296549 [found with GoPubMed]
55: Bioorg Med Chem 2009 Apr;17(7):2718-23
Binary and ternary inclusion complexes of finasteride in HPbetaCD and polymers: preparation and characterization
Asbahr, Ana Carolina C, Franco, Luzia, Barison, Andersson, Silva, Caroline W P, Ferraz, Humberto G, Rodrigues, Letícia N C, Departamento de Farmácia, Universidade Federal do Paraná, Av. Lothario Meissner, 632, Curitiba, PR 80210-170, Brazil.
The aim of this study was to determine whether inclusion complexes between 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) and finasteride (FIN) are formed, and to characterize these. Equimolar FIN/HPbetaCD solid systems in the presence or absence of 0.1% (w/v) of polyvinylpyrrolidone K30 (PVP K30) or 0.3% of chitosan were prepared by coevaporation and freeze-drying methods. The systems were characterized by phase solubility, NMR, DSC, and XRD analysis. The results suggest that true binary and ternary inclusion complexes were formed.
PMID: 19282187 [found with GoPubMed]
56: J Agric Food Chem 2009 Apr;57(8):3298-307
Optimization of the film-forming and storage conditions of chitosan as an antimicrobial agent
Fernandez-Saiz, P, Lagarón, J M, Ocio, M J, Novel Materials and Nanotechnology Laboratory, Instituto de Agroquímica y Tecnologia de Alimentos (IATA), CSIC, Valencia, Spain
The aim of this work was to assess the antimicrobial capacity of chitosan-based films obtained by a dissolution and solvent evaporation (solvent casting) method at various temperatures (i.e., 37, 80, and 120 degrees C) on the growth of Staphylococcus aureus and Salmonella spp. bacteria. The effect of temperature (4, 23, 37 degrees C) and relative humidity (RH; 0, 75%) during storage on the biocide performance was also investigated. Color parameters and ATR-FTIR spectra were analyzed for each sample to investigate the relationship between structural and/or chemical alterations in the films during storage and biocide performance. The results indicated that films formed at 37 and 80 degrees C presented a significant inhibitory effect for both types of bacteria; however, when cast at 120 degrees C, the films ceased to exhibit antimicrobial properties. Curiously, chitosonium acetate films were seen to diminish to a large extent their biocide properties when stored at 23 degrees C and 75% RH for 2 months or alternatively when stored and 37 degrees C and 0% RH over the same period of time. In good agreement with this behavior the FTIR results indicated that under the previous conditions a significant fraction of the biocide carboxylate chemistry remained in the polymer after contact with the bacterial solution due to a strong reduction in cast film solubility. Because biopolymer active species migration from the film to the culture media is needed for the biomaterial to exhibit measurable antimicrobial effect, proper control of temperature and humidity during film formation and storage is necessary to design the optimum performance of chitosan as a biocide.
PMID: 19281273 [found with GoPubMed]
57: Virology 2009 Apr;387(1):89-97
Hybrid of baculovirus and galactosylated PEI for efficient gene carrier
Kim, You-Kyoung, Choi, Jae Young, Jiang, Hu-Lin, Arote, Rohidas, Jere, Dhananjay, Cho, Myung-Haing, Je, Yeon Ho, Cho, Chong-Su, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, South Korea
Baculovirus, containing an appropriate eukaryotic promoter, is considered an attractive approach for an efficient and safe gene delivery vehicle. However, the drawbacks of baculovirus, such as the lack of specificity and the inactivation of baculovirus by the complement system in human serum, negatively affect efficient gene delivery. Therefore, a hybrid system utilizing the positive aspects of both viral and non-viral vector systems would be useful to overcome the obstacles of either system alone. In this study, we constructed a hybrid system composed of baculovirus (B) and galactosylated polyethylenimine (GP)/DNA complexes through electrostatic interaction. The resulting GP/B hybrid had suitable physicochemical properties and low cytotoxicity for use in gene therapy. Furthermore, the GP/B significantly enhanced transduction efficiency and showed good cell-specificity compared to either viral or non-viral vector systems. These results suggest that the GP/B hybrid system can be used in gene therapy to enhance transduction efficiency and hepatocyte specificity.
PMID: 19272627 [found with GoPubMed]
58: Carbohydr Res 2009 Apr;344(6):801-7
Chitosan-graft poly(p-dioxanone) copolymers: preparation, characterization, and properties
Wang, Xiu-Li, Huang, Yan, Zhu, Jiang, Pan, Yan-Bo, He, Rui, Wang, Yu-Zhong, Center for Degradable and Flame-Retardant Polymeric Materials (ERCEPM-MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610064, China.
A new biodegradable copolymer of chitosan and poly(p-dioxanone) (PPDO) was prepared through a protection-graft-deprotection procedure using N-phthaloyl-chitosan as an intermediate. PPDO terminated with the isocyanate group was allowed to react with hydroxyl groups of the N-phthaloyl-protected chitosan, and then the phthaloyl group was cleaved to give the free amino groups. The length of PPDO graft chains can be controlled easily by using the prepolymers of PPDO with different molecular weights. The resulting products were thoroughly characterized with FT-IR, (1)H NMR, TG, DSC, SEM, and WAXD. The copolymers were used as drug carriers for sinomenine (7,8-didehydro-4-hydroxy-3,7-dimethoxy-17-methyl-9alpha,13alpha,14alpha-morphinan-6-one) and these exhibited a significant controlled drug-releasing behavior whether in artificial gastric juice or in neutral phosphate buffer solution.
PMID: 19268919 [found with GoPubMed]
59: Mol Pharm 2009 Apr;6(2):345-352
Immunological Effects and Membrane Interactions of Chitosan Nanoparticles
Pattani, A, Patravale, V B, Panicker, L, Potdar, P D
Department of Molecular Medicine and Biology, Jaslok Hospital and Research Centre, Mumbai-400026, India, Department of Pharmaceutical Science and Technology, Institute of Chemical Technology, Mumbai-400019, India, and Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400049, India.
The objective of this study was to investigate the in vitro and in vivo effects of blank chitosan nanoparticles on various molecular markers such as nitric oxide (NO) production, IL-6 gene expression, and lymphocyte proliferation involved in the wound healing process. In addition, the membrane effects of chitosan nanoparticles were evaluated using phospholipid vesicles as a model membrane. Peripheral blood mononuclear cells (PBMC) were treated with blank chitosan nanoparticles, and the effect on NO production, IL-6 gene expression, and lymphocyte proliferation was evaluated. It was observed that IL-6 gene expression was not induced at any of the doses used; however, a statistically significant dose-dependent increase in NO production was observed at doses above 68.18 mug/mL equivalent to chitosan. Furthermore, chitosan nanoparticles showed a statistically significant and dose-dependent lymphocyte proliferation as compared to the control (P < 0.05). It was observed that blank chitosan nanoparticles resulted in strong membrane perturbation when evaluated by differential scanning calorimetry studies. The in vivo effects of the blank chitosan nanoparticles were evaluated using a wound healing model. Blank chitosan nanoparticles showed significantly higher NO production in vivo as compared to the control. Overall, the study clearly indicates the immunoactivating nature of chitosan nanoparticles and their strong membrane interactive potential.
PMID: 19265445 [found with GoPubMed]
60: Cancer Genet Cytogenet 2009 Apr;190(1):8-14
Selection of optimal sites for TGFB1 gene silencing by chitosan-TPP nanoparticle-mediated delivery of shRNA
Wang, So-Ly, Yao, Hui-Hua, Guo, Ling-Ling, Dong, Liang, Li, Shi-Gang, Gu, Yong-Ping, Qin, Zheng-Hong, Department of Pathology, Soochow University School of Medicine, Suzhou, China
Most human tumors produce high levels of TGF-beta1, whose autocrine and paracrine actions promote tumor cell invasiveness and metastasis. Currently, many experimental therapies that target TGFB1 have utilized antisense DNA or RNA interference (RNAi). Despite the great potential of RNAi, the selection of effective target sites and proper delivery systems for short hairpin RNA (shRNA) remains a significant issue. Here, we used chitosan nanoparticle-mediated delivery of a shRNA-expressing vector to inhibit TGFB1 expression in the human rhabdomyosarcoma cell line RD. Knockdown of TGFB1 by shRNA resulted in a decrease in RD cell growth in vitro and tumorigenicity in nude mice. The efficiency of TGFB1 gene silencing varied with the selection of targeting sites. These data suggest that chitosan nanoparticle-mediated delivery of an shRNA produces efficient TGFB1 knockdown in rhabdomyosarcoma cells and may be a method of choice for shRNA delivery for gene therapy.
PMID: 19264227 [found with GoPubMed]
61: Biomacromolecules 2009 Apr;10(4):858-64
Chitosan-coated wires: conferring electrical properties to chitosan fibers
Meyer, W Lee, Liu, Yi, Shi, Xiao-Wen, Yang, Xiaohua, Bentley, William E, Payne, Gregory F, Center for Biosystems Research, University of Maryland Biotechnology Institute, 5115 Plant Sciences Building, College Park, Maryland 20742, USA
There is considerable interest in creating convenient biosensing platforms that couple the capabilities of biology for selective detection with the power of electronics for signal transduction. Here, the capabilities of a polymeric fiber for facile biofunctionalization is coupled with the signal transduction capabilities of a conducting wire to generate a hybrid platform that can be viewed as either a biofunctionalized wire or a conducting fiber. Integral to this hybrid platform is the interface material chitosan that enables simple electrical signals to be employed to biofunctionalize conducting wires. Specifically, we use cathodic signals to direct chitosan to electrodeposit onto gold wires and anodic signals to conjugate proteins (e.g., for biosensing) to the chitosan-coated wire. In addition, the chitosan-coating is permeable to small molecules, which allows for the electrical detection of electrochemically active compounds that are either present in the external environment or generated by a biofunctionalized chitosan coating. The capabilities for biofunctionalization and transduction are demonstrated for the detection of glucose by chitosan-coated wires functionalized with the enzyme glucose oxidase. Chitosan-coated wires (or alternatively conducting chitosan fibers) are a simple platform that may permit multiplexed biosensing outside the laboratory.
PMID: 19260679 [found with GoPubMed]
62: J Agric Food Chem 2009 Apr;57(7):2699-704
In vitro antioxidant activities of low-molecular-weight polysaccharides with various functional groups
Chen, Szu Kai, Tsai, Min Lang, Huang, Jin Ru, Chen, Rong Huei, Department of Food Science, National Taiwan Ocean University, 2 Pei-Ning Road, Keelung, Taiwan 20224, Republic of China
The objectives of this study were to evaluate the effect of different functional groups of sulfate, amine, and hydroxyl and/or their ionized groups on in vitro antioxidant capacities of low-molecular-weight polysaccharides (LMPS) prepared from agar (LMAG), chitosan (LMCH), and starch (LMST), respectively, and to elucidate their structure-activity relationship. Ascorbic acid and ethylenediaminetetraacetic acid (EDTA) were used as positive controls. The in vitro antioxidant capacities of LMAG and LMCH were higher than that of LMST in the DPPH radical, superoxide radical, hydrogen peroxide, and nitric oxide radical scavenging and ferrous metal-chelating capacities. The different scavenging capacities may be due to the combined effects of the different sizes of the electron-cloud density and the different accessibility between free radical and LMPS, which, in turn, depends upon the different hydrophobicities of the constituent sugars.
PMID: 19256513 [found with GoPubMed]
63: Carbohydr Res 2009 Apr;344(6):815-9
Recombinant expression of a chitosanase and its application in chitosan oligosaccharide production
Liu, Ya-Li, Jiang, Shu, Ke, Zu-Min, Wu, Hai-Shui, Chi, Cheng-Wu, Guo, Zhan-Yun, Zhejiang Feng'an Biopharmaceutical, Xianju 317300, China
Recently, considerable attention has been focused on chitosan oligosaccharides (COSs) due to their various biological activities. COSs can be prepared by enzymatic degradation of chitosan, which is the deacetylation product of chitin, one of the most abundant biopolymers in nature. In the current study, we recombinantly expressed a chitosanase and used it for COS preparation. A bacillus-derived GH8 family chitosanase with a 6xHis tag fused at its N-terminal was expressed in the Escherichia coli strain BL21(DE3) as a soluble and active form. Its expression level could be as high as 500 mg/L. Enzymatic activity could reach approximately 140,000 U/L under our assay conditions. The recombinant chitosanase could be purified essentially to homogeneity by immobilized metal-ion affinity chromatography. The enzyme could efficiently convert chitosan into monomer-free COS: 1g of enzyme could hydrolyze about 100 kg of chitosan. Our present work has provided a cheap chitosanase for large-scale COS production in industry.
PMID: 19254792 [found with GoPubMed]
64: J Biol Chem 2009 Apr;284(16):10610-7
Aromatic residues in the catalytic center of chitinase A from Serratia marcescens affect processivity, enzyme activity, and biomass converting efficiency
Zakariassen, Henrik, Aam, Berit Bjugan, Horn, Svein J, Vårum, Kjell M, Sørlie, Morten, Eijsink, Vincent G H, Department of Chemistry, Biotechnology, and Food Science, The Norwegian University of Life Sciences, 1432 As, Norway
The processive Serratia marcescens chitinases A (ChiA) and B (ChiB) are thought to degrade chitin in the opposite directions. A recent study of ChiB suggested that processivity is governed by aromatic residues in the +1 and +2 (aglycon) subsites close to the catalytic center. To further investigate the roles of aromatic residues in processivity and to gain insight into the structural basis of directionality, we have mutated Trp(167), Trp(275), and Phe(396) in the -3, +1, and +2 subsites of ChiA, respectively, and characterized the hydrolytic activities of the mutants toward beta-chitin and the soluble chitin-derivative chitosan. Although the W275A and F396A mutants showed only modest reductions in processivity, it was almost abolished by the W167A mutation. Thus, although aglycon subsites seem to steer processivity in ChiB, a glycon (-3) subsite seems to be adapted to do so in ChiA, in line with the notion that the two enzymes have different directionalities. Remarkably, whereas all three single mutants and the W167A/W275A double mutant showed reduced efficiency toward chitin, they showed up to 20-fold higher activities toward chitosan. These results show that the processive mechanism is essential for an efficient conversion of crystalline substrates but comes at a large cost in terms of intrinsic enzyme speed. This needs to be taken into account when devising enzymatic strategies for biomass turnover.
PMID: 19244232 [found with GoPubMed]
65: J Drug Target 2009 Apr;17(3):225-34
Amoxicillin, clarithromycin, and omeprazole based targeted nanoparticles for the treatment of H. pylori
Ramteke, Suman, Ganesh, N, Bhattacharya, S, Jain, Narendra K, School of Pharmaceutical Sciences, Rajiv Gandhi Technical University, Bhopal, India.
The aim of the present study was to develop and characterize targeted sustained release nanoparticles of chitosan-glutamic acid conjugates containing triple therapy for Helicobacter pylori to improve its therapeutic effect and reduce its dose-related side effect. The chitosan-glutamate nanoparticles were prepared by using the ionotropic gelation method. The particle sizes of systems ranged between 550 nm and 900 nm. Percent drug entrapment and release profiles of amoxicillin, clarithromycin, and omeprazole in simulated gastric fluid (pH 1.2) were determined using high-performance liquid chromatography. The maximum % drug entrapment and % yield of formulations were about 60-90% and 73-88%, respectively. The stability of the drugs was assessed in simulated gastric fluid (pH 1.2). In vitro antibacterial efficacy of optimized formulations containing monotherapy and triple therapy on isolated culture of H. pylori was assessed. In vivo clearance study and histopathological study were also carried out on Swiss albino mice to evaluate the efficacy of triple therapy containing targeted nanosystem for the treatment of H. pylori. The proposed delivery system holds promise at optimizing the treatment of H. pylori.
PMID: 19241256 [found with GoPubMed]
66: FEMS Microbiol Lett 2009 Apr;293(1):79-84
Molecular characterization and antifungal activity of a family 46 chitosanase from Amycolatopsis sp. CsO-2
Saito, Akihiro, Ooya, Takaaki, Miyatsuchi, Daisuke, Fuchigami, Hiroko, Terakado, Kanako, Nakayama, Shin-ya, Watanabe, Takeshi, Nagata, Yoshiho, Ando, Akikazu, Department of Bioresource Chemistry, Faculty of Horticulture, Chiba University, Matsudo, Chiba, Japan
An actinomycete strain, Amycolatopsis sp. CsO-2, produces a 27-kDa chitosanase. To reveal the molecular characteristics of the enzyme, its corresponding gene ctoA was cloned by a reverse genetic technique, based on the N-terminal amino acid sequence of the protein. The encoded CtoA protein was deduced to be composed of 286 amino acids, including a putative signal peptide (1-48), and exhibited 83% identity in the amino acid sequence with the family 46 chitosanases from Streptomyces sp. N174 or Nocardioides sp. N106. The active recombinant CtoA protein was successfully overproduced in Escherichia coli. The mutant protein E22Q, in which the glutamic acid residue 22 was replaced with glutamine, abolished the chitosanase activity, showing that the Glu22 residue is required for the enzymatic activity. CtoA exhibited antifungal activity against Rhizopus oryzae, which is known to produce chitosan probably as a cell wall component. In contrast, E22Q did not inhibit the growth of the fungus, suggesting that chitosan-hydrolyzing activity is essential for the antifungal activity. It is noteworthy that the antifungal effect of CtoA against R. oryzae was drastically enhanced by the simultaneous addition of the family 19 chitinase ChiC from Streptomyces griseus.
PMID: 19236484 [found with GoPubMed]
67: Virology 2009 Apr;386(2):438-47
Enhanced resistance to coxsackievirus B3-induced myocarditis by intranasal co-immunization of lymphotactin gene encapsulated in chitosan particle
Yue, Yan, Xu, Wei, Hu, Linkun, Jiang, Zhenggang, Xiong, Sidong, Institute for Immunobiology, Department of Immunology, Shanghai Medical College of Fudan University, 138 Yi Xue Yuan Road, Shanghai 200032, PR China
Coxsackievirus B3 (CVB3) is a gastrointestinal virus causing myocarditis in human and mice. An ideal vaccine for CVB3-myocarditis requires both humoral and cellular immunity at systemic and mucosal compartments. We described here an enhancing strategy for chitosan-pVP1 vaccine by co-immunizing with lymphotactin (LTN) gene, a T cell-attractive-chemokine, encapsulated in chitosan particle to provide more protection against CVB3. Mice were intranasally co-immunized with 4 doses of chitosan-DNA vaccines separately encapsulating VP1 and LTN plasmids by 2 week-intervals and challenged with CVB3 4 weeks after the last immunization. Compared with chitosan-pVP1 alone, co-immunization with chitosan-pLTN significantly increased high-avidity-neutralizing antibody levels in serum and in intestinal mucosa, and promoted systemic and mucosal Th1 and CD8(+)CTL immune responses. Accordingly, enhanced resistance to CVB3-myocarditis was evidenced by reduced myocardial viral load, profound subsidence of myocarditis and increased survival rate. This strategy represents a promising platform for Th1 polarization and protection against mucosal infectious pathogens.
PMID: 19233446 [found with GoPubMed]
68: Carbohydr Res 2009 Apr;344(6):825-9
Synthesis and antimicrobial activity of the Schiff base from chitosan and citral
Jin, Xiaoxiao, Wang, Jiangtao, Bai, Jie, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China
Chitosan, a biocompatible, biodegradable, non-toxic polymer, is prepared from chitin, which is the second most naturally occurring biopolymer after cellulose. The Schiff base of chitosan was synthesized by the reaction of chitosan with citral working under high-intensity ultrasound. The effect of the molar ratio of chitosan to citral, reaction time, and temperature on the yield has been investigated. The optimal conditions were a temperature of 50 degrees C, a molar ratio of chitosan to citral of 1:6, and a reaction time of 10h. The maximum yield achieved was 86.4% under optimum conditions. The structure of the Schiff base was characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction studies. The strong peaks at 1648.3 and 1610.6 cm(-1) are due to C=N and C=C stretching vibrations. The results confirmed that amino groups on chitosan reacted with citral to form the Schiff base. The antimicrobial activities of chitosan and Schiff base of chitosan were investigated against Escherichia coil, Staphylococcus aureus, and Aspergillus niger. The results indicate that the antimicrobial activity of the Schiff base increases with an increase in the concentration. It was also found that the antimicrobial activity of the Schiff base was stronger than that of chitosan.
PMID: 19230865 [found with GoPubMed]
69: Biomacromolecules 2009 Apr;10(4):892-9
Degradation of chitosans with chitinase G from Streptomyces coelicolor A3(2): production of chito-oligosaccharides and insight into subsite specificities
Heggset, Ellinor B, Hoell, Ingunn A, Kristoffersen, Marius, Eijsink, Vincent G H, Vårum, Kjell M, Norwegian Biopolymer Laboratory, Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
We have studied the degradation of soluble heteropolymeric chitosans with a bacterial family 19 chitinase, ChiG from Streptomyces coelicolor A3(2), to obtain insight into the mode of action of ChiG, to determine subsite preferences for acetylated and deacetylated sugar units, and to evaluate the potential of ChiG for production of chito-oligosaccharides. Degradation of chitosans with varying degrees of acetylation was followed using NMR for the identity (acetylated/deacetylated) of new reducing and nonreducing ends as well as their nearest neighbors and using gel filtration to analyze the size distribution of the oligomeric products. Degradation of a 64% acetylated chitosan yielded a continuum of oligomers, showing that ChiG operates according to a nonprocessive, endo mode of action. The kinetics of the degradation showed an initial rapid phase dominated by cleavage of three consecutive acetylated units (A; occupying subsites -2, -1, and +1), and a slower kinetic phase reflecting the cleavage of the glycosidic linkage between a deacetylated unit (D, occupying subsite -1) and an A (occupying subsite +1). Characterization of isolated oligomer fractions obtained at the end of the initial rapid phase and at the end of the slower kinetic phase confirmed the preference for A binding in subsites -2, -1, and +1 and showed that oligomers with a deacetylated reducing end appeared only during the second kinetic phase. After maximum conversion of the chitosan, the dimers AD/AA and the trimer AAD were the dominating products. Degradation of chitosans with varying degrees of acetylation to maximum degree of scission produced a wide variety of oligomer mixtures, differing in chain length and composition of acetylated/deacetylated units. These results provide insight into the properties of bacterial family 19 chitinases and show how these enzymes may be used to convert chitosans to several types of chito-oligosaccharide mixtures.
PMID: 19222164 [found with GoPubMed]
70: Talanta 2009 Apr;78(2):491-7
Chitosan modified ordered mesoporous silica as micro-column packing materials for on-line flow injection-inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples
Chen, Dahui, Hu, Bin, Huang, Chaozhang, Department of Chemistry, Wuhan University, Wuhan 430072, China
A novel adsorbent of chitosan chemically modified ordered mesoporous silica was synthesized and employed as a solid phase extraction (SPE) material for flow injection (FI) micro-column preconcentration on-line coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) determination of trace heavy metals V, Cu, Pb, Cd and Hg in environmental water samples. The factors affecting separation and preconcentration of target heavy metals such as pH, sample flow rate and volume, eluent concentration and volume, interfering ions were investigated. Under the optimized experimental conditions, an enrichment factor of 20 and sampling frequency of 10h(-1) were obtained. The detection limits of the method for V, Cu, Pb, Cd and Hg were 0.33, 0.30, 0.96, 0.05 and 0.93 ng mL(-1), and the relative standard deviations (RSDs) were 2.8%, 6.7%, 1.8%, 4.0% and 5.3% (n=7, C=10 ng mL(-1)), respectively. The adsorption capacities of chitosan modified ordered mesoporous silica for V, Cu, Pb, Cd, and Hg were found to be 16.3, 21.7, 22.9, 12.2 and 13.5 mg g(-1), respectively. In order to validate the developed method, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values. The proposed method has also been applied to the determination of trace heavy metals in natural water samples with satisfactory results.
PMID: 19203614 [found with GoPubMed]
71: Bioelectrochemistry 2009 Apr;75(1):77-82
A microbial biosensor based on bacterial cells immobilized on chitosan matrix
Odaci, Dilek, Timur, Suna, Telefoncu, Azmi, Ege University, Faculty of Science, Biochemistry Department, 35100 Bornova-Izmir, Turkey
A bio-electrochemical system consisting of Gluconobacter oxydans DSM 2343 cells as a biological material and carbon nanotube (CNT)-free and CNT-modified chitosan as immobilizing matrices has been developed. The measurement was based on the respiratory activity of the cells estimated by the oxygen consumption at -0.7 V (versus the Ag|AgCl reference electrode) due to the metabolic activity in the presence of substrates. The system was calibrated and dependence of signal amplitude on the measuring conditions and cell amount was studied as well as the substrate specificity, pH, temperature and working potential. The biosensors (CNT-modified and unmodified) were demonstrated for the quantification of glucose in the range of 0.05-1.0 mM, at 30 degrees C and pH 7.0 with the 40 s of response time. The linear relationships between sensor response (y; microA/cm(2)) and substrate concentration (x; mM) were defined by the equations of y=1.160x+0.151 (R(2)=0.990) and y=1.261x+0.197 (R(2)=0.982), respectively. All other data were also given as comparison of two systems one with CNT-modified and CNT-free.
PMID: 19196553 [found with GoPubMed]
72: Appl Biochem Biotechnol 2009 Apr;157(1):23-35
Purification and characterization of thermostable chitinase from Bacillus licheniformis SK-1
Kudan, Sanya, Pichyangkura, Rath, Biochemistry Department, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
Chitinase was purified from the culture medium of Bacillus licheniformis SK-1 by colloidal chitin affinity adsorption followed by diethylamino ethanol-cellulose column chromatography. The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular size and pI of chitinase 72 (Chi72) were 72 kDa and 4.62 (Chi72) kDa, respectively. The purified chitinase revealed two activity optima at pH 6 and 8 when colloidal chitin was used as substrate. The enzyme exhibited activity in broad temperature range, from 40 to 70 degrees C, with optimum at 55 degrees C. It was stable for 2 h at temperatures below 60 degrees C and stable over a broad pH range of 4.0-9.0 for 24 h. The apparent K (m) and V (max) of Chi72 for colloidal chitin were 0.23 mg ml(-1) and 7.03 U/mg, respectively. The chitinase activity was high on colloidal chitin, regenerated chitin, partially N-acetylated chitin, and chitosan. N-bromosuccinamide completely inhibited the enzyme activity. This enzyme should be a good candidate for applications in the recycling of chitin waste.
PMID: 19190863 [found with GoPubMed]
73: J Colloid Interface Sci 2009 Apr;332(2):280-90
New modified chitosan-based adsorbent for defluoridation of water
Jagtap, Sneha, Thakre, Dilip, Wanjari, Snehal, Kamble, Sanjay, Labhsetwar, Nitin, Rayalu, Sadhana, Environmental Materials Unit, National Environmental Engineering Research Institute, Nehru Marg, Nagpur 400 020, India
In the present study, the metal-binding property of chitosan is used to incorporate titanium metal and applied as an adsorbent for fluoride adsorption. Titanium macrospheres (TM) were synthesized by a precipitation method and characterized by FTIR, SEM, and XRD. The Langmuir and Freundlich adsorption models were applied to describe the adsorption equilibrium and the adsorption capacities were calculated. Thermodynamic parameters of standard free energy change (DeltaG(o)), standard enthalpy change (DeltaH(o)), and standard entropy change (DeltaS(o)) were also calculated. The effects of various physico-chemical parameters such as pH, initial concentration, adsorbent dose, and the presence of coexisting anions were studied. The fluoride uptake was maximum at neutral pH 7 and decreased in acidic and alkaline pH. The presence of coexisting anions has a negative effect on fluoride adsorption. TM was found to have very fast kinetics in the first 30 min and then the rate slowed down as equilibrium was approached. A comparison of fluoride removal in simulated and field water shows a high adsorption capacity in simulated water.
PMID: 19181328 [found with GoPubMed]
74: Biomaterials 2009 Apr;30(12):2329-39
In vivo evaluation of safety and efficacy of self-assembled nanoparticles for oral insulin delivery
Sonaje, Kiran, Lin, Yu-Hsin, Juang, Jyuhn-Huarng, Wey, Shiaw-Pyng, Chen, Chiung-Tong, Sung, Hsing-Wen, Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC
A variety of approaches have been studied in the past to overcome the problems encountered with the oral delivery of insulin, but with little success. In this study, self-assembled nanoparticles (NPs) with a pH-sensitive characteristic were prepared by mixing the anionic poly-gamma-glutamic acid solution with the cationic chitosan solution in the presence of MgSO(4) and sodium tripolyphosphate. The in vitro results found that the transport of insulin across Caco-2 cell monolayers by NPs appeared to be pH-dependent; with increasing pH, the amount of insulin transported decreased significantly. An in vivo toxicity study was performed to establish the safety of the prepared NPs after oral administration. Additionally, the impact of orally administered NPs on the pharmacodynamics (PD) and pharmacokinetics (PK) of insulin was evaluated in a diabetic rat model. The in vivo results indicated that the prepared NPs could effectively adhere on the mucosal surface and their constituted components were able to infiltrate into the mucosal cell membrane. The toxicity study indicated that the NPs were well tolerated even at a dose 18 times higher than that used in the PD/PK study. Oral administration of insulin-loaded NPs demonstrated a significant hypoglycemic action for at least 10h in diabetic rats and the corresponding relative bioavailability of insulin was found to be 15.1+/-0.9%. These findings suggest that the NPs prepared in the study are a promising vehicle for oral delivery of insulin.
PMID: 19176244 [found with GoPubMed]
75: Talanta 2009 Apr;78(1):120-5
Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in hybrid organic-inorganic film of chitosan/sol-gel/carbon nanotubes
Kang, Xinhuang, Wang, Jun, Tang, Zhiwen, Wu, Hong, Lin, Yuehe, College of Science, Guangdong Ocean University, Zhanjiang, 524088, PR China
A hybrid organic-inorganic nanocomposite film of chitosan/sol-gel/multi-walled carbon nanotubes was constructed for the immobilization of horseradish peroxidase (HRP). This film was characterized by scanning electron microscopy. Direct electron transfer (DET) and bioelectrocatalysis of HRP incorporated into the composite film were investigated. The results indicate that the film can provide a favorable microenvironment for HRP to perform DET on the surface of glassy carbon electrodes with a pair of quasi-reversible redox waves and to retain its bioelectrocatalytic activity toward H(2)O(2).
PMID: 19174213 [found with GoPubMed]
76: Food Microbiol 2009 Apr;26(2):151-6
Use of natural compounds to improve the microbial stability of Amaranth-based homemade fresh pasta
Del Nobile, M A, Di Benedetto, N, Suriano, N, Conte, A, Lamacchia, C, Corbo, M R, Sinigaglia, M, Department of Food Science, University of Foggia, Via Napoli 25, 71100 Foggia, Italy.
A study on the use of natural antimicrobial compounds to improve the microbiological stability of refrigerated amaranth-based homemade fresh pasta is presented in this work. In particular, the antimicrobial activity of thymol, lemon extract, chitosan and grapefruit seed extract (GFSE) has been tested against mesophilic and psychrotrophic bacteria, total coliforms, Staphylococcus spp., yeasts and moulds. A sensory analysis on both fresh and cooked pasta was also run. Results suggest that chitosan and GFSE strongly increase the microbial acceptability limit of the investigated spoilage microorganisms, being the former the most effective. Thymol efficiently reduces the growth of mesophilic bacteria, psychrotrophic bacteria and Staphylococcus spp., whereas it does not affect, substantially, the growth cycle of total coliforms. Lemon extract is the less effective in preventing microbial growth. In fact, it is able to delay only total mesophilic and psychrotrophic bacterial evolution. From a sensorial point of view no significant differences were recorded between the control samples and all the types of loaded amaranth-based pasta.
PMID: 19171256 [found with GoPubMed]
77: Biosens Bioelectron 2009 Apr;24(8):2447-51
Single-crystal CeO2 nanocubes used for the direct electron transfer and electrocatalysis of horseradish peroxidase
Xiao, Xiaoling, Luan, Qingfen, Yao, Xin, Zhou, Kebin, College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing 100049, China
A new horseradish peroxidase (HRP) third-generation electrochemical biosensor based on ceria nanocubes (CeO(2)-NCs) and chitosan (Chit) was developed. The single-crystalline, uniform and size-controlled CeO(2)-NCs have been synthesized by hydrothermal method. HRP was immobilized in CeO(2)-NCs and Chit film on the glass carbon electrode (HRP/CeO(2)/Chit/GCE). Compared with HRP-chitosan modified electrode (HRP/Chit/GCE), HRP/CeO(2)/Chit/GCE exhibited a pair of more obvious redox peaks at -0.348 V (versus Ag/AgCl). Experimental results indicate CeO(2)-NCs greatly promoted the electron transfer between HRP and GCE. The immobilized HRP exhibited direct electrochemical behavior toward the reduction of hydrogen peroxide (H(2)O(2)). The resulting biosensor showed a linear range of 1-150 microM and a detection limit of 0.26 microM estimated at a signal-to-noise ratio of 3. Stability and reproducibility of the biosensor were also studied. The biological activity of HRP immobilizing in the composite film was characterized by UV-vis and FTIR spectra.
PMID: 19168345 [found with GoPubMed]
78: Biomaterials 2009 Apr;30(12):2276-83
The effect of a layer-by-layer chitosan-heparin coating on the endothelialization and coagulation properties of a coronary stent system
Meng, Sheng, Liu, Zongjun, Shen, Li, Guo, Zhang, Chou, Laisheng L, Zhong, Wei, Du, Qiangguo, Ge, Junbo, Department of Macromolecular Science and The Key Laboratory of Molecular Engineering of Polymers, Ministry of Education, Fudan University, Shanghai 200433, People's Republic of China
A biomacromolecular layer-by-layer coating process of chitosan/heparin onto a coronary stent is designed for the acceleration of the re-endothelialization and healing process after coronary stent deployment. The results of in vitro culturing of porcine iliac artery endothelial cells as well as the measurements of the APTT, PT and TT supported the rationale that the combination of chitosan and heparin could bring both endothelial cell compatibility and haemocompatibility to the stent surface. A porcine coronary injury model and arteriovenous shunt model were used for the further evaluation of the application of this kind of surface-modified stainless steel stent in vivo. The final results proved that this facile coating approach could significantly promote re-endothelialization and was safer compared with bare metal stents for its much improved anticoagulation property.
PMID: 19168214 [found with GoPubMed
79: J Pharm Biomed Anal 2009 Apr;49(3):655-9
Evaluation of surface and microstructure of differently plasticized chitosan films
Bajdik, János, Marciello, Marzia, Caramella, Carla, Domján, Attila, Süvegh, Károly, Marek, Tamás, Pintye-Hódi, Klára, Department of Pharmaceutical Technology, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary
Surface and structural investigations of natural biopolymer (chitosan) films containing various conventionally applied hydrophilic plasticizers (glycerol and poly(ethylene glycol) 400) were performed and the results were compared, with the aim of acquiring new information concerning the formation of these plasticized films. The surface tests revealed that the water uptake, the water-binding properties (moisture content) and the polarity were higher for the film containing glycerol as plasticizer. Positronium lifetime measurements and NMR studies performed to evaluate the effects of the plasticizer on the polymer structure demonstrated relevant differences in the effects of the plasticizers. The influence of glycerol on the structure of the film formed was more intensive than that of PEG 400. It can be concluded that the surface properties of the films, which are very important for their storage and application, cannot be established exactly by means of structural tests. Both surface and structural tests must be performed before the formulation of this type of plasticized mucoadhesive films.
PMID: 19162425 [found with GoPubMed]
80: Biomaterials 2009 Apr;30(12):2340-8
Long-circulating polymeric nanoparticles bearing a combinatorial coating of PEG and water-soluble chitosan
Sheng, Yan, Liu, Changsheng, Yuan, Yuan, Tao, Xinyi, Yang, Fan, Shan, Xiaoqian, Zhou, Huanjun, Xu, Feng, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, PR China
A major obstacle in the development of polymeric nanoparticles (NPs) as effective drug delivery vesicles is the rapid clearance from blood. In order to realize a significant prolongation in blood circulation, a combinatorial design, covalent attachment of polyethylene glycol (PEG) to polylactic acid (PLA) and physical adsorption of water-soluble chitosan (WSC) to particle surface, has been developed for surface modification of PLA NPs. Two types of WSC, cationic partially deacetylated chitin (PDC) and anionic N-carboxy propionyl chitosan sodium (CPCTS) were investigated. All the NPs formulated in the size range of 100-200nm were prepared by a modified w/o/w technique and physicochemically characterized. In vitro phagocytosis by mouse peritoneal macrophage (MPM), in vivo blood clearance and biodistribution following intravenous administration in mice, of these NPs labeled with 6-coumarin, were evaluated. The presence of WSC, whether alone or with PEG, highly improved the surface hydrophilicity as well as suspension stability of NPs. Their surface charge was greatly affected by the WSC coating, being close to neutrality for PEG/PDC NPs and highly negative in the case of PEG/CPCTS NPs. In comparison to NPs treated with PEG or WSC alone, the synergistic action of PEG and WSC strongly inhibited the macrophage uptake and extended the circulation half-life (t(1/2)) with concomitant reduced liver sequestration. Particularly, PEG/PDC NPs showed the most striking result with regard to their performance in vitro and in vivo. Calculated t(1/2) of PEG/PDC NPs and PEG/CPCTS NPs was 63.5h and 7.1h, respectively, much longer than that of control PEG/PVA NPs (1.1h). More WSC materials need to be evaluated, but the present data suggest that, a combinatorial coating of PEG and PDC greatly prolongs the systemic circulation of NPs and represents a significant step in the development of long-circulating drug delivery carriers.
PMID: 19150737 [found with GoPubMed]
81: Int J Biol Macromol 2009 Apr;44(3):249-56
Synthesis of novel pH-sensitive chitosan graft copolymers and micellar solubilization of paclitaxel
Li, Hongxia, Liu, Jia, Ding, Song, Zhang, Can, Shen, Wenbin, You, Qidong, Centre for Drug Discovery, China Pharmaceutical University, Nanjing, PR China
Herein, highly pH-sensitive graft copolymers, N-octyl-N-(2-carboxylbenzoyl) chitosan derivatives, were synthesized and characterized by FTIR, (1)H NMR, (13)C NMR, differential scanning calorimetry and X-ray diffraction spectrometry. The polymers can form micelles solublizing paclitaxel, with critical micellar concentrations ranged from 0.07 to 0.32mg/ml, drug-loading rate ranged from 30.7% to 65.3% and entrapment efficiency ranged from 44.2% to 61.4%. Additionally, the result shows that the micelles display highly sensitivity to mildly acidic pH while reasonably stable at physiologic pH, which might pave the way for building pharmaceutical nanocarriers specifically releasing cargo at certain pathological sites of body.
PMID: 19150369 [found with GoPubMed]
82: Int J Biol Macromol 2009 Apr;44(3):229-35
Photopolymerization of methacrylated chitosan/PNIPAAm hybrid dual-sensitive hydrogels as carrier for drug delivery
Han, Jing, Wang, Kemin, Yang, Dongzhi, Nie, Jun, Beijing University of Chemical Technology, PR China
A series of hybrid hydrogels based on glycidyl methacrylated chitosan (CS-GMA) and N-isopropylacrylamide (NIPAAm) were designed and prepared via photopolymerization technology. The hydrogels were characterized by Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC) and optical transmittance. The interior morphology of hydrogels was investigated by scanning electron microscopy (SEM). The swelling experiment results revealed that hybrid hydrogel exhibited combined pH and temperature sensitivities. Acid orange 8 (AO8) and 5-flurouracil (5-Fu) were selected as model drugs for examining their release from hydrogels. The results suggested that hydrogel composition and pH value of buffer solution had great influences on release profiles.
PMID: 19146871 [found with GoPubMed]
83: Int J Pharm 2009 Apr;371(1-2):163-9
SPION-loaded chitosan-linoleic acid nanoparticles to target hepatocytes
Lee, Chang-Moon, Jeong, Hwan-Jeong, Kim, Se-Lim, Kim, Eun-Mi, Kim, Dong Wook, Lim, Seok Tae, Jang, Kyu Yoon, Jeong, Yong Yeon, Nah, Jae-Woon, Sohn, Myung-Hee, Biotracer Imaging Laboratory, Chonbuk National University Medical School, Jeonju, Jellabuk-Do 561-712, Republic of Korea
The aim of this study was to develop a novel polymeric magnetic nanoprobe as an MRI contrast agent to target hepatocytes, as well as to evaluate the targeting ability of the nanoprobe with MRI in vivo. Superparamagnetic iron oxide nanocrystals (SPIONs) were synthesized by a thermal decomposition and seed growth method. An 1-ethyl-3-(3-(dimethylamino)-propyl) carbodiimide (EDC)-mediated reaction coupled water-soluble chitosan (WSC) to linoleic acid (LA). Twelve-nanometer-sized SPIONs were incorporated into the core of self-assembled WSC-LA nanoparticles. The morphology and size distribution of the SPION-loaded WSC-LA nanoparticles (SCLNs) were determined by transmittance electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The encapsulation of SPIONs in the WSC-LA nanoparticles reduced the cytotoxicity of bare iron particles and enhanced their dispersion ability in water. The clustering of SPIONs into WSC-LA nanoparticles showed ultrasensitive magnetic behavior. After in vivo intravascular SCLN injection, MRI revealed relative signal enhancement in the liver. The localization of SCLN in hepatocytes was confirmed by Prussian blue staining and TEM analysis. We have successfully developed an ultrasensitive SCLN that effectively targets hepatocytes. The SCLN can be used as a contrast agent to aid in the diagnosis of hepatic diseases.
PMID: 19138733 [found with GoPubMed]
84: Biomaterials 2009 Apr;30(11):2102-11
A nanoscale drug-entrapment strategy for hydrogel-based systems for the delivery of poorly soluble drugs
Chen, Mei-Chin, Tsai, Hung-Wen, Liu, Chin-Tang, Peng, Shu-Fen, Lai, Wei-Yun, Chen, Shiang-Jiuun, Chang, Yen, Sung, Hsing-Wen, Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC
The hydrophilic nature of hydrogel matrices makes them disadvantageous to entrap poorly soluble therapeutic agents and greatly restricts their applications as drug-delivery systems. In this study, we demonstrated that sustained delivery of lipophilic drugs in hydrogel-based devices can be readily achieved by enhancing retention of drugs within micelles. This nanoscale drug-entrapment strategy was applied to develop a polymeric drug-eluting stent. Sirolimus, a lipophilic anti-proliferative/immunosuppressive drug, was entrapped into the hydrophobic core of Pluronic L121 micelles and then blended in a chitosan-based strip and crosslinked by an epoxy compound to fabricate test stents. It was found that the use of such a nanoscale drug-entrapment strategy was able to significantly increase the loading efficiency of lipophilic drugs, prevent the drug from aggregation and beneficially reduce its initial burst release; thus, the duration of drug release was extended considerably. When implanting the stent in rabbit infrarenal abdominal aortas, in-stent restenosis was markedly reduced and less inflammatory reaction was observed, while unfavorable effects such as delayed endothelial healing caused by the overdose of sirolimus could be significantly evaded.
PMID: 19135720 [found with GoPubMed]
85: Biomaterials 2009 Apr;30(10):1910-7
Formation of a human-derived fat tissue layer in P(DL)LGA hollow fibre scaffolds for adipocyte tissue engineering
Morgan, Suzanne M, Ainsworth, Ben J, Kanczler, Janos M, Babister, Jodie C, Chaudhuri, Julian B, Oreffo, Richard O C, Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton SO166YD, UK
Development of adipose tissue-engineering strategies, where human bone marrow stromal cells (HBMSC) are combined with three-dimensional scaffolds, is likely to prove valuable for soft tissue restoration. In this study, we assessed the function of poly(DL-lactide-co-glycolide) (P(DL)LGA) hollow fibres in facilitating the development of HBMSC-derived adipocytes for advancement of an associated adipocyte layer. The large surface area of 75:25 P(DL)LGA fibres facilitated the rapid generation of extensive adipocyte aggregates from an undifferentiated HBMSC monolayer, where the fat-laden cells stained positive with Oil Red O and expressed the adipocyte marker, fatty acid binding protein 3 (FABP3). Following implantation subcutaneously in severely compromised immunodeficient mice, the adipogenic phenotype of the PLGA-adipocyte graft was maintained for up to 56 days. Confocal microscopy showed associated LipidTOX Deep Red neutral lipid staining in an (FL)P(DL)LGA fibre-adipocyte graft after 56 days, critical evidence demonstrating maintenance of the adipocyte phenotype in the subcutaneous graft. To support adipose tissue advancement in a defined volume, the P(DL)LGA-adipocyte scaffold was encapsulated within alginate/chitosan hydrogel capsules (typical diameters, 4.0 mm). In a 28-day in vivo trial in immunodeficient mice, clusters of the capsules were maintained at the subcutaneous site. An adipocyte tissue layer advancing within the surrounding hydrogel was demonstrated.
PMID: 19135718 [found with GoPubMed]
86: Int J Pharm 2009 Apr;371(1-2):170-6
Intravesical cationic nanoparticles of chitosan and polycaprolactone for the delivery of Mitomycin C to bladder tumors
Bilensoy, Erem, Sarisozen, Can, Esendagli, Günes, Dogan, A Lale, Aktas, Yesim, Sen, Murat, Mungan, N Aydin, Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Technology, 06100 Sihhiye-Ankara, Turkey.
Cationic nanoparticles of chitosan (CS), poly-epsilon-caprolactone coated with chitosan (CS-PCL) and poly-epsilon-caprolactone coated with poly-L-lysine (PLL-PCL) were developed to encapsulate intravesical chemotherapeutic agent Mitomycin C (MMC) for longer residence time, higher local drug concentration and prevention of drug loss during bladder discharge. Nanoparticle diameters varied between 180 and 340 nm depending on polymer used for preparation and coating. Zeta potential values demonstrated positive charge expected from cationic nanoparticles. MMC encapsulation efficiency depended on hydrophilicity of polymers since MMC is water-soluble. Encapsulation was increased by 2-fold for CS-PCL and 3-fold for PLL-PCL as a consequence of hydrophilic coating. Complete drug release was obtained with only CS-PCL nanoparticles. On the other hand, CS and PLL-PCL nanoparticles did not completely liberate MMC due to strong polymer-drug interactions which were elucidated with DSC studies. As far as cellular interaction was concerned, CS-PCL was the most efficient formulation for uptake of fluorescent markers Nile Red and Rhodamine123 incorporated into nanoparticles. Especially, CS-PCL nanoparticles loaded with Rhodamine123 sharing hydrophilic properties with MMC were selectively incorporated by bladder cancer cell line, but not by normal bladder epithelial cells. CS-PCL nanoparticles seem to be promising for MMC delivery with respect to anticancer efficacy tested against MB49 bladder carcinoma cell line.
PMID: 19135514 [found with GoPubMed]
87: Int J Pharm 2009 Apr;371(1-2):156-62
Chitosan N-betainates/DNA self-assembly nanoparticles for gene delivery: in vitro uptake and transfection efficiency
Gao, Yu, Zhang, Zhiwen, Chen, Lingli, Gu, Wangwen, Li, Yaping, Center for Drug Delivery System, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
The aim of this work is to investigate the effect of betaine substitution degree of chitosan N-betainates (CsB) on cellular uptake, cytotoxicity and transfection efficiency of CsB/DNA complex nanoparticles (CsBNs) against COS-7 and MDA-MB-468 cells. The polymers with three substitution degrees (CsB12, CsB47 and CsB85) complexed with pDNA formed CsBN12s, CsBN47s and CsBN85s. The CsBNs showed less pH dependency with smaller particle size and higher zeta potential than that of chitosan/pDNA complex nanoparticles (CsNs) at neutral pH. CsBN85s showed stronger cellular uptake than that of CsBN47s or CsBN12s. CsBNs showed higher cytotoxicity than CsNs, and a trend increasing toxicity with substitution degree increasing. In COS-7 cells, the transfection efficiency increased with the substitution degree increasing, while the opposite result was observed in MDA-MB-468 cells. Chitosan modified with betaine could increase its ability to facilitate DNA uptake and its cytotoxicity, both of which showed the influence on transfection efficiency. It was able to increase cellular uptake and transfection efficiency of complex nanoparticles in COS-7 cells to increase betaine substitution of CsB, however, the higher sensitivity of MDA-MB-468 cells to CsBs led to decreased transfection efficiency due to the increased cytotoxicity with betaine substitution increasing. The predominant role of cellular uptake or toxicity in affecting transfection efficiency was different in two cell lines. These results provided an important guidepost for further development of chitosan derivatives/pDNA complexes as non-viral gene vectors.
PMID: 19135139 [found with GoPubMed]
88: Macromol Biosci 2009 Apr;9(4):317-25
Morphology controlled growth of chitosan-bound microtubes and a study of their biocompatibility and antibacterial activity
Henricus, Marsiyana M, Fath, Karl R, Menzenski, Monica Z, Banerjee, Ipsita A, Department of Chemistry, Fordham University, Bronx, New York 10458, USA
Self-assembled peptide microtubes are fabricated with the biopolymer chitosan. The microtubes are covalently attached to chitosan and the morphology of the chitosan assembled on the surface of the microtubes can be tuned by altering the pH of the growth solution. Cytotoxicity studies in the presence of mouse embryonic fibroblasts indicate that the chitosan-bound microtubes are highly biocompatible and the cells are able to survive and proliferate at a similar rate to the control. Antibacterial studies in the presence of E. coli prove that the chitosan-bound microtubes are bactericidal. This simple method for the development of biocompatible microstructures will facilitate cell targeting, fabrication of efficient carrier devices, and the preparation of highly efficient antibacterial materials.
PMID: 19127599 [found with GoPubMed]
89: Int J Pharm 2009 Apr;371(1-2):142-7
Enhanced electrostatic interaction between chitosan-modified PLGA nanoparticle and tumor
Yang, Rui, Shim, Won-Sik, Cui, Fu-De, Cheng, Gang, Han, Xu, Jin, Qing-Ri, Kim, Dae-Duk, Chung, Suk-Jae, Shim, Chang-Koo, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
In our previous study, lung tumor-specific targeting of paclitaxel was achieved in mice by intravenous administration of chitosan-modified paclitaxel-loaded PLGA nanoparticles (C-NPs-paclitaxel). Transient formation of aggregates in the blood stream followed by enhanced trapping in the capillaries was proposed as a mechanism of the lung-specific accumulation of paclitaxel. In the present study, the mechanism of tumor lung preferential accumulation of paclitaxel from C-NPs-paclitaxel was investigated. Zeta potential and in vitro cellular cytotoxicity (A549 cells and CT-26 cells) of C-NPs-paclitaxel, and in vitro uptake of coumarin 6 to these cells from chitosan-modified coumarin 6 containing PLGA nanoparticles (C-NPs-coumarin 6) were examined as a function of pH (6.8, 7.4 and 8.0). The zeta potential of C-NPs-paclitaxel increased as the medium pH became more acidic. In vitro uptake of coumarin 6 by A549 cells and CT-26 cells was enhanced at lower pH for C-NPs-coumarin 6. In vitro cytotoxicity experiment with C-NPs-paclitaxel demonstrated enhanced cytotoxicity as the pH became more acidic. Therefore, enhanced electrostatic interaction between chitosan-modified PLGA nanoparticles and acidic microenvironment of tumor cells appears to be an underlying mechanism of lung tumor-specific accumulation of paclitaxel from C-NPs-paclitaxel.
PMID: 19118614 [found with GoPubMed]
90: J Mater Sci Mater Med 2009 Apr;20(4):991-9
Investigation of polymeric amphiphilic nanoparticles as antitumor drug carriers
Zhang, Jing, Chen, Xi Guang, Liu, Cheng Sheng, Park, Hyun Jin, College of Marine Life Science, Ocean University of China, 5# Yushan Road, Qingdao, 266003, People's Republic of China
In this paper, polymeric amphiphilic nanoparticles based on oleoyl-chitosan (OCH) with different degrees of substitution (DS, 5%, 11% and 27%) were prepared by Oil/Water emulsification method. Mean diameters of the nanoparticles were 327.4 nm, 255.3 nm and 192.6 nm, respectively. Doxorubicin (DOX) was efficiently loaded into OCH nanoparticles and provided a sustained released after a burst release in PBS. These nanoparticles showed no cytotoxicity to mouse embryo fibroblasts (MEF) and low hemolysis rates (<5%). The results of SDS-PAGE indicated that bovine calf serum (BCS) adsorption on OCH nanoparticles was inhibited by smaller particle size. Cellular uptake was evaluated by incubating fluorescence labeled OCH nanoparticles with human lung carcinoma cells (A549) and mouse macrophages (RAW264.7). Cellular uptake of OCH nanoparticles was time--and concentration--dependent. Finding the appropriate incubation time and concentration of OCH nanoparticles used as drug carriers might decrease phagocytic uptake, increase cancer cell uptake and ultimately improve therapeutic efficiency of antitumor therapeutic agents.
PMID: 19083084 [found with GoPubMed]
91: J Mater Sci Mater Med 2009 Apr;20(4):935-41
Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using chitosan and citric acid
Song, Ho-Yeon, Esfakur Rahman, A H M, Lee, Byong-Taek, Department of Microbiology, School of Medicine, Soonchunhyang University, 366-1 Ssangyoung-dong, Cheonan City, Chungnam, 330-090, South Korea
In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan solution as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA) and calcium sulfate hemihydrate (CSH) powders as the solid phase was prepared. Four groups containing different percentages (0-30%) of calcium sulfate hemihydrate (CSH, CaSO(4) . 0.5H(2)O) were investigated. Initial setting times for IBS with CSH were longer than those without CSH. The setting times for all compositions were in the range of 25-45 min. The injectability was improved by the addition of CSH in the present system. Scanning electron microscopy images showed that fiber-like crystallization appeared in the cements. The enhancement of crystallinity was confirmed by XRD profiles where the peak intensity of HAp increased with incubation time and the addition of CSH. Also, the compressive strength increased with the addition of CSH. The maximum compressive strength obtained for IBS was with 20% CSH after 28-day incubation in 100% humidity at 37 degrees C.
PMID: 19052849 [found with GoPubMed]
92: J Mater Sci Mater Med 2009 Apr;20(4):917-23
Novel electrohydrodynamic preparation of porous chitosan particles for drug delivery
Pancholi, Ketan, Ahras, Nassim, Stride, Eleanor, Edirisinghe, Mohan, Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
Uniform spherical chitosan particles of size 10 microm diameter. In this study, by reducing surface tension of a high viscosity chitosan suspension, it was found that smaller diameter particles could be prepared. Chitosan solutions were electrosprayed in the stable cone-jet mode to systematically study the relationship between particle diameter, viscosity and surface tension. Increasing viscosity resulted in larger diameter particles with a broad size distribution, but decreasing surface tension had the opposite effect. Results show that a chitosan solution having a viscosity of approximately 80 mPa s can be used to prepare chitosan particles of diameter approximately 2.5 microm which on drying reduced to particles of 500 nm.
PMID: 19034624 [found with GoPubMed]
93: J Mater Sci Mater Med 2009 Apr;20(4):897-907
Multilayer coatings on biomaterials for control of MG-63 osteoblast adhesion and growth
Kirchhof, Kristin, Hristova, Kamelia, Krasteva, Natalia, Altankov, George, Groth, Thomas, Biomedical Materials Group, Department of Pharmaceutics and Biopharmaceutics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, 06120, Halle (Saale), Germany
Here, the layer-by-layer technique (LbL) was used to modify glass as model biomaterial with multilayers of chitosan and heparin to control the interaction with MG-63 osteoblast-like cells. Different pH values during multilayer formation were applied to control their physico-chemical properties. In the absence of adhesive proteins like plasma fibronectin (pFN) both plain layers were rather cytophobic. Hence, the preadsorption of pFN was used to enhance cell adhesion which was strongly dependent on pH. Comparing the adhesion promoting effects of pFN with an engineered repeat of the FN III fragment and collagen I which both lack a heparin binding domain it was found that multilayers could bind pFN specifically because only this protein was capable of promoting cell adhesion. Multilayer surfaces that inhibited MG-63 adhesion did also cause a decreased cell growth in the presence of serum, while an enhanced adhesion of cells was connected to an improved cell growth.
PMID: 19034623 [found with GoPubMed]
94: J Mater Sci Mater Med 2009 Apr;20(4):949-57
Preparation and HL-7702 cell functionality of titania/chitosan composite scaffolds
Zhao, Li, Chang, Jiang, Zhai, Wanyin, Shanghai Tissue Engineering Research and Development Center, Shanghai, China.
Titania/chitosan composite scaffolds were prepared through a freeze-drying technique. The composite scaffolds were highly porous with the average pore size of 120-300 microm, and the titania (TiO(2)) powders were uniformly dispersed on the surface of the pore walls. The compressive strength of the composite scaffolds was significantly improved compared to that of pure chitosan scaffolds. Composite scaffold with 0.3 of TiO(2)/chitosan weight ratio showed the maximum compressive strength of 159.7 +/- 21 kPa. Hepatic immortal cell line HL-7702 was used as seeding cells on the scaffolds, and after different culture periods, cell attachment and function was analyzed. HL-7702 cells attached on the pore walls of the scaffolds with the spheroid shape after 1 day of culture, but more cell aggregations formed within the TiO(2)/chitosan composite scaffolds as compared to pure chitosan scaffolds. Liver-specific functions, albumin secretion and urea synthesis were detected using a spectrometric method. The results showed that albumin secretion and urea synthesis rate of HL-7702 cells slightly decreased with the culture time, and there was no significant difference between composite scaffolds and pure chitosan scaffolds. In conclusion, the TiO(2)/chitosan composite scaffolds possessed an improved mechanical strength compared to pure chitosan scaffolds and supported the attachment and functional expression of hepatocyte, implying their potential application in liver tissue engineering.
PMID: 19034620 [found with GoPubMed]
95: J Mater Sci Mater Med 2009 Apr;20(4):943-8
Effects of alkylated-chitosan-DNA nanoparticles on the function of macrophages
Liu, L X, Song, C N, Song, L P, Zhang, H L, Dong, X, Leng, X G, Tianjin Key Laboratory of Biomedical materials, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
Chitosan could form nanoparticles with DNA through electrostatic interaction, and hence protect the DNA from enzymatic degradation. Numerous studies have been working on modifying chitosan aiming at improving its transgenic efficacy. While the modification of chitosan with alkyl group has been shown to significantly improve the cell transfection efficiency, little is known about its impact on its biocompatibility. The current study was performed to investigate the impact of alkylated-chitosan/DNA nanoparticles on the function of the murine macrophage through observing its phagocytic activity and production of pro-inflammatory cytokines (IL-1beta, IL-6, IL-10, IL-12 and TNF-alpha). Our results demonstrated that the alkylated-chitosan/DNA nanoparticles at the concentration of 20 microg/ml DNA content had no significant impact on the production of cytokines and phagocytic activity of the macrophages as compared with the unmodified chitosan/DNA nanoparticles and negative control even after 24 h co-incubation. It suggested that the modification of chitosan with alkyl group should not have negative impact on the function of the macrophages.
PMID: 19020960 [found with GoPubMed]
96: Drug Dev Ind Pharm 2009 Apr;35(4):387-95
Formulation and characterization of nanoemulsion-based drug delivery system of risperidone
Kumar, Mukesh, Pathak, Kamla, Misra, Ambikanandan, Department of Pharmaceutics Rajiv Academy for Pharmacy, Mathura, Uttar Pradesh, India
Risperidone nanoemulsion (NE) and mucoadhesive NE formulations were successfully prepared by the spontaneous emulsification method (titration method) using Capmul MCM as the oily phase on the basis of solubility studies. The NE formulation containing 8% oil, 44% S(mix), 48% (wt/wt) aqueous phase that displayed an optical transparency of 99.82%, globule size of 15.5 +/- 2.12 nm, and polydispersity of 0.172 +/- 0.02 was selected for the incorporation of mucoadhesive components. The mucoadhesive formulation that contained 0.5% by weight of chitosan displayed highest diffusion coefficient that followed Higuchi model was free from nasal ciliotoxicity and stable for 3 months.
PMID: 19016058 [found with GoPubMed]
97: Macromol Biosci 2009 Apr;9(4):354-60
Mechanical reinforcement of continuous flow spun polyelectrolyte complex fibers
Granero, Alberto J, Razal, Joselito M, Wallace, Gordon G, in het Panhuis, Marc, ARC Center of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, School of Chemistry, University of Wollongong, Northfields Avenue, Wollongong, NSW, Australia
A simple continuous flow wet-spinning method to achieve mechanical reinforcement of the two oppositely charged biopolymers chitosan and gellan gum is described. The mechanical properties of these biopolymers are influenced by the order of addition. Using a facile method for mechanical reinforcement of gellan gum/chitosan fibers resulted in increases in Young's modulus, tensile strength, and toughness. Spinning gellan gum into chitosan resulted in the strongest fibers. We show that our fibers can provide a mechanical alternative for bio-fibers without the need of cross-linking. It is demonstrated that the fibers become ionically conducting in the presence of water vapor.
PMID: 19003850 [found with GoPubMed]
98: Biochem Biophys Res Commun 2009 Apr;381(4):466-70
The specificity of chitosan in promoting branching morphogenesis of progenitor salivary tissue
Yang, Tsung-Lin, Young, Tai-Horng, Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
Chitosan has been shown to be effective in regulating progenitor salivary tissue morphogenesis, however, the specificity of chitosan effects remains unclear. To assess the regulatory ability of chitosan in salivary gland morphogenesis, progenitor salivary tissue from embryonal submandibular gland (SMG) was cultured in chitosan-containing medium. It was found that soluble chitosan was able to promote SMG branching in a dose-dependent manner. The effect was chitosan-specific and was not reproduced by substrates with similar chemical structures or other polymeric molecules of natural or synthetic origin. Furthermore, the branch-promoting effects were molecular weight-dependent. In addition, following digestion with lysozyme, chitinase, or chitosanase, digested chitosan was unable to reproduce the similar effects. In all, this study clarifies the specificity and preferential activity of chitosan in enhancing branching morphogenesis of progenitor salivary tissue and highlights its potential utility for application in salivary tissue regeneration.
PMID: 18983827 [found with GoPubMed]
99: Int J Parasitol 2009 Apr;39(5):599-606
Mucosal delivery of native and recombinant protein vaccines against Trichostrongylus colubriformis
McClure, S J, CSIRO Livestock Industries, F.D. McMaster Laboratory, Locked Bag 1, Armidale DC, NSW 2350, Australia.
This paper describes a series of five pilot trials to test the feasibility of inducing a protective mucosal immune response against a non-blood-feeding intestinal nematode by delivery of antigens across the mucosal epithelium. A number of antigen preparations from Trichostrongylus colubriformis (viable larvae, larval homogenate and recombinant 17kDa excretory-secretory protein) were delivered to the luminal surface of the mucosal epithelium overlying jejunal or rectal lymphoid tissue in cellulose or chitosan formulations. Significant protection was induced following delivery of viable larvae, larval homogenate or recombinant protein to the epithelium overlying rectal Peyer's patches, and recombinant protein to the epithelium overlying jejunal Peyer's patches. Viable larvae were associated with a jejunal IgE/IgG1 response, while the 17kDa antigen was associated with a jejunal IgA response. The results demonstrate that delivery of Trichostrongylus native and recombinant antigens across the epithelium overlying rectal lymphoid patches can result in significant protective immunity even in the absence of adjuvant. They warrant the further investigation of appropriate mucosal delivery methods and adjuvants for induction of protective mucosal responses to stages and species of gastrointestinal helminths which do not ingest serum antibodies.
PMID: 18952092 [found with GoPubMed]
100: Bioprocess Biosyst Eng 2009 Apr;32(3):407-14
Study on immunosensor based on gold nanoparticles/chitosan and MnO2 nanoparticles composite membrane/Prussian blue modified gold electrode
Ling, Shujuan, Yuan, Ruo, Chai, Yaqin, Zhang, Tingting, Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest China University, 400715, Chongqing, People's Republic of China.
A novel and convenient immunosensor, based on the electrostatic adsorption characteristics between the positively charged MnO(2) nanoparticles (nano-MnO(2)) and chitosan (CS) composite membrane (nano-MnO(2) + CS) and the negatively charged prussian blue (PB), was prepared for the detection of carcinoembryonic antigen (CEA). Firstly, PB was electro-deposited on the surface of the gold electrode in the constant potential, and then nano-MnO(2) + CS was adsorbed onto PB-modified electrode surface. Subsequently, Gold nanoparticles (nano-Au) were electro-deposited on the nano-MnO(2) + CS-modified electrode to immobilize antibody CEA (anti-CEA). Finally, bovine serum albumin (BSA) was employed to block sites against nonspecific binding. In our study, cyclic voltammetry (CV) and scanning electron microscopy (SEM) were used to characterize the fabricated process of the immunosensor. The immunosensor put up a rapid response time, high sensitivity and stability. Under the optimized conditions, cyclic voltammograms(CVs) determination of CEA displayed a broader linear response to CEA in two ranges, from 0.25 to 8.0 ng/mL, and from 8.0 to 100 ng/mL, with a relative low-detection limit of 0.083 ng/mL at three times the background and noise. The originality of the preparation of the immunosensor lies in not only using the synergistic effect of two kinds of nanomaterials (nano-MnO(2) and nano-Au) to immobilize anti-CEA, but also using nano-MnO(2) + CS to furnish a media transferring electron path. What is more, the researched methodology was efficient and potentially attractive for clinical immunoassays.
PMID: 18923847 [found with GoPubMed]