Publications in January 2017 - layer-by-layer coating with chitosan
The year 2017 started in January with a high number of new publications about chitosan and chitosan derivatives (383 articles). Top countries in publishing about chitosan were China (75), the United States (39) and India (25). This time we focus on the layer-by-layer (LbL) assembly of chitosan mostly together with other biomaterials and possible applications.
According to gopubmed, 16 articles were published about the application of layer-by-layer technique and chitosan in January 2017. Top terms in those publications can be found in the following table:
|Actin crosslink formation||3|
Table: Top Terms connected with chitosan and layer-by-layer in January 2017. Source: gopubmed
There is a great interest in the design and manufacturing of nanostructured materials for application in biomedicine. The layer-by-layer technique is a commonly used method for functionalizing materials. Films are build-up by stacks of oppositely charged materials. We picked out two articles about coating with chitosan by LbL technique, to present them in more detail.
Tuning cell adhesive properties via layer-by-layer assembly of chitosan and alginate
Silva J. M., Garcia J. R., Reis R. L. et al. Acta Biomaterialia 51, 279-293. Epub January 2017
The understanding of mechanisms between cells and multilayers is important for development of suitable coatings. The authors investigated the influence of cross-linking and additional coating of the multilayers on cell adhesion. Multilayer consisted of medium molecular weight Chitosan (MW 150-300 kDa, 90% DDA, Heppe Medical Chitosan) and low viscosity alginate.
- Cross-linking improved mechanical properties
- Cross-linking altered adhesion of human umbilical vein endothelial cells (HUVECs)
- Coating with chitosan/alginate multilayers on top of cross-linked films decreased cell adhesion, spreading and differentiation
Conclusion: The authors from Portugal successfully developed a system of chitosan/alginate multilayers by layer-by-layer technique with tunable cell adhesive properties. Successful transition from cell-adhesive to cell-resistant multilayered films was shown.
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Silk fibroin organization induced by chitosan in layer-by-layer films: Application as a matrix in a biosensor
Delezuk J. A. M., Pavinatto A., Moraes M. L. et al. Carbohydrate Polymers, 155: 146-151. doi: 10.1016/j.carbpol.2016.08.060. January 2017
Researcher from Brazil developed chitosan/silk fibroin layer-by-layer films as matrix to immobilize the enzyme phytase. They tested three different chitosan samples with distinct molecular weights for creation of LbL films. Phytase is used for detection of phytin acid, a bioactive substance, which can be found e.g. in food products and hinders the uptake of minerals like magnesium and calcium into the small intestine.
- Conformation change from random coils to β-sheets for silk fibroin (SF) with high molecular weight chitosan (CHH)
- Successful application of CHH/SF LbL films on interdigitated gold electrodes and functionalisation with phytase
- Detection of phytic acid (10-9 M) by impedance spectroscopy
- High sensitivity of measurement system is assisted by CHH/SF matrix
Conclusion: Chitosan/silk fibroin layer-by-layer films were successfully created and tested. CHH/SF LbL films were selected as matrix for immobilization of phytase. High sensitive detection of phytic acid by immobilized phytase was supported by CHH/SF LbL films and therefore, could be a promising approach to improve other biosensors and biodevices.