Silk Fibroin/Poly (vinyl alcohol) Hydrogel Cross-Linked with Dialdehyde Starch for Wound Dressing Applications

Silk fibroin (SF) with the anti-bacterial property can be used in many fields including medical applications. However, the preparation of SF into a desired form is difficult due to its brittleness and compatibility. The purpose of this study was to prepare and characterize hydrogel containing SF and poly(vinyl alcohol) (PVA) crosslinked with dialdehyde starch (DAS) without the need for a conventional chemical crosslinker. The compatibility of SF and PVA, the gel fraction, and the swelling ratio of the SF:PVA hydrogel were improved when crosslinked with DAS. Moreover, the addition of DAS affected the porosity and the water vapor transmission rate (WVTR) of the hydrogel. The optimal ratio for preparation of the hydrogel was 50:50 SF:PVA with 5 wt% DAS, which exhibited a high gel fraction of 98 % and a 245-fold gel swelling compared with that of the dried hydrogel. The consequent loss of weight suggested the stability of hydrogel in water. The WVTR of the hydrogel was 2280 +/- 114 g.m(-2).day(-1) close to the range suitable for maintaining the appropriate fluid balance in the wound bed for wound healing without risking wound dehydration. The hydrogel improvement properties propose the potential to expanding the applications of SF:PVA hydrogels as wound dressing materials.