Construction of bilayered porous γ-polyglutamic acid/konjac glucomannan hydrogels as potential dressings

Nowadays hydrogels are widely used as wound dressings. In this study, double-layered porous breathable water-retaining hydrogel composed of γ-poly (glutamic acid), poly (vinyl alcohol) and konjac glucoman was constructed by repeated freeze-thawing method. The result showed that the bi-layered hydrogel hold excellent swelling ratio (885.3%) and water retention capacity (70 h), water vapor transmission rate (2379 g·m−2·d−1), mechanical property and bacterial-barrier property. If the bi-layered hydrogel was used as dressings, the macropores in the lower layer was able to absorb a large amount of exudate from the wound, and the proper air permeability, excellent water absorption and water retention property could maintain appropriate humidity to keep the wound healing moisture. Moreover, the small pores in the upper layer had the ability to prevent bacteria from reaching the wound surface and causing infection. Therefore the double-layer hydrogel has great potential as a dressing and provides a good idea for the design of hydrogel dressings.