Antibacterial, multifunctional hydrogel based on carboxymethylchitosan

Hydrogels can have versatile applications in biomedicine by forming a 3D network. In the study presented here, an antibacterial, adhesive, self-repairing hydrogel was prepared from carboxymethylchitosan (CMC) and oligomeric polycyanidin (OPC) and the influence of OPC content was investigated.

FACILE PREPARATION OF ANTIBACTERIAL, MULTIFUNCTIONAL HYDROGEL BASED ON CARBOXYMETHYLCHITOSAN AND OLIGOMERIC PROCYANIDIN

He Y, Guo S, Chang R, Zhang D, Ren Y, Guan F, Yao M. Facile preparation of antibacterial hydrogel with multi-functions based on carboxymethyl chitosan and oligomeric procyanidin. RSC Adv. 2022 Jul 21;12(32):20897-20905. doi: 10.1039/d2ra04049b. PMID: 35919176; PMCID: PMC9301940.

Hydrogels are water-soluble polymers that have a unique 3D structure. As a result, they have a high similarity to biological tissues as well as the extracellular matrix, which makes them interesting for biomedical applications.

In particular, self-healing adhesive hydrogels that form in situ are of interest for this purpose. They are injectable, fill irregular structures, can repair themselves in case of a defect, and adhere to a surface over a longer period of time. This is essential, for example, for hydrogels with an antimicrobial effect, which can be used to prevent infections in the long term. Especially against the background of a growing number of microbial resistances, new alternative strategies to antibiotics have to be found.

The chitosan derivative caboxymethylchitosan (CMC) has a natural antimicrobial effect. CMC has improved solubility and better biocompatibility compared to conventional chitosan. In addition, CMC forms a 3D network that can be improved by crosslinking agents. Phenol-rich compounds, such as grape-derived oligomeric polycyanides (OPC), can be used for this purpose.

In the presented study, a rapid, simple approach will be developed to produce an injectable, self-healing, adhesive and antibacterial hydrogel based on CMC and OPC. The properties of the hydrogel were adjusted by the OPC content (2, 4, 6% → CMC/OPC₂, CMC/OPC₄, CMC/OPC₆). The CMC content was 3 %.

RESULTS

• Detection of formation H-bridges between CMC and OPC by FTIR
• Gelation time of 125.3 s for CMC/OPC₂, 18.7 s for CMC/OPC₄, and 5.3 s for CMC/OPC₆ →decreases with increasing OPC content
• Improvement in mechanical properties of hydrogels with increasing OPC content
• Increasing swelling capacity with increasing OPC content (CMC/OPC₂: 153.1%, CMC/OPC₄: 180.6%, CMC/OPC₆: 219.1%)
• Degradation of CMC/OPC hydrogels after 11 days in vitro
• All hydrogels exhibited a well-defined, 3D cross-linked structure via SEM
• Observation of good self-healing ability for all hydrogels prepared
• CMC/OPS hydrogels are able to adhere to different surfaces e.g. metal. plastic or glass
• Easy adhesion to biological tissues such as heart, liver, lung or skin
• Adhesion strength of up to 17.7 kPas for CMC/OPC₆
• In case of direct contact: Inhibition of S. aureus greater than 95% for CMC/OPC₄ and CMC/OPC₆, only 81% for CMC/OPC₂, all greater than 95% for E. coli

Conclusions: In the presented study, an antibacterial adhesive self-healing hydrogel was successfully prepared from CMC and OPC using a simple method. The OPC content had an influence on the gelation time, mechanical properties and swelling capacity. In addition, all the hydrogels prepared showed good antibacterial properties. As a result, the CMC/OPC hydrogels have great potential for antibacterial applications.

Link to article: https://pubs.rsc.org/en/content/articlelanding/2022/ra/d2ra04049b