Preparation and characterization of methoxy-poly(ethylene glycol) side chain grafted onto chitosan as a wound dressing film

Abstract

Chitosan has received extensive attention as a biomedical material; however, the poor solubility of chitosan is the major limiting factor in its utilization. In this study, chitosan-based biomaterials with improved aqueous solubility were synthesized. Two molecular weights (750 Da and 2000 Da) of methoxypoly(ethylene glycol) (mPEG) were grafted onto chitosan (mPEG-g-chitosan) to form a 100-m-thick plastic film as a wound dressing. The chemical structures of the mPEG-g-chitosan copolymers were confirmed using Fourier transform infrared spectroscopy (FTIR), and the thermal properties were characterized using thermogravimetry analysis (TGA). Their microstructures were observed using scanning electron microscopy (SEM). The other properties were analyzed via the swelling ratio, tensile strength, elongation, and water vapor transmission rate (WVTR). Biocompatibility evaluations through biodegradability, cytotoxicity, and antimicrobial effect studies were also performed. The obtained mPEG-g-chitosan copolymers were soluble in slightly acidic aqueous solutions (pH 6.5) at a concentration of 10 wt. The optimal mPEG-g-chitosan hydrogels had swelling ratios greater than 100 and WVTRs greater than 2000 g/m2/day. Their performance against Staphylococcus aureus will be subjected to further improvements with respect to medical applications.