Enhancement of Poly(vinyl alcohol) Hydrogel Properties by N-Succinyl Chitosan and Mesona chinensis Extract for Use as Wound Dressings

Hydrogels composed of different ratios of poly(vinyl alcohol), N-succinyl chitosan (NSC), and Mesona chinensis extract, for use as a wound dressing, were synthesized via thermal polymerization. Potassium persulfate was chosen as the initiator and glutaraldehyde as the crosslinking agent. NSC was prepared by modification of chitosan with succinic anhydride. It was found that this preparation method gave a high gel fraction percentage. The structures of the prepared hydrogels were characterized by Fourier-transform infrared spectroscopy, and their morphology by scanning electron microscopy (SEM). In addition, water transport properties, mechanical properties and cytotoxicity were also studied. The SEM results show that the hydrogels exhibited porous structures and that pore size and size distribution increased with increasing NSC content. Hydrogel-water interactions and water transport properties were also studied in terms of swelling ratio, equilibrium water retention, and water vapour transmission rate. These showed an increase, from 637 to 1240 %, 17.8 to 21.4 %, and 110 to 121 g h−1 m−2 respectively with an increase in NSC content. These gels exhibit a lower water vapour transmission rate compared to that of second and third degree burns but higher than normal skin. Similarly, NSC improved the mechanical properties, presented in terms of stress and percentage strain, of the hydrogels. The stress, percentage strain, and Young’s modulus were found to increase from 15 to 32 kPa, 197 to 294 %, and 0.078 to 0.133 kPa respectively. The hydrogels can be considered to be non-toxic based on the in vitro cytotoxicity assay results. In conclusion, the results showed that, by varying composition, hydrogel properties can be tuned to the specific requirements of an ideal wound dressing.