Effect of molecular weight of chitosan oligomer on pva-Ag-chitosan oligomer hydrogel for wound healing

Abstract

Gel and thin film are types of hydrogel that has good adhesive property for making wound dressing. They are created by cross-linking many polymers. In this study, the main purpose is to evaluate influences of different molecular weights of chitosan oligomer on PVA – Ag – COS hydrogel for wound healing. Various chitosan oligomers are created by chitosan degradation according to 2 methods based on using H2O2 oxidative treatment. Therein, method 2 which has the assistance of microwave radiation is the most suitable one for cutting chitosan. The degraded chitosan were characterized by UV – vis spectrometry, gel permeation chromatography, and Fourier transform infrared (FTIR). The analyzed results showed that the molecular weight of chitosan oligomer is descending within ascending reaction time. Chitosan oligomer chains are shorter than original chitosan and have many carbonyl groups appearances. These generated chitosan oligomers are used in fabricating PVA – Ag – COS hydrogel. In combination of PVA – Ag with chitosan oligomer at the ratio of 50:50, gels and films are mainly diverse depending on the molecular weight of chitosan oligomer. The characterizations of hydrogel were evaluated by tensile testing, and antibacterial testing. The result showed that the lighter the chitosan oligomer weight of hydrogel is, the lower the mechanical properties of film are, but the higher the antibacterial activities are. Besides, PVA – Ag – COS hydrogel can fight against negative Gram bacteria well. In contrast, it is pretty worst to fight against positive Gram bacteria. The minimum inhibitory concentration of gel with all chitosan oligomer is 3.125%. KEYWORDS: hydrogel, thin film, gel, chitosan, chitosan oligomer, molecular weight