Pluronic/chitosan hydrogels containing epidermal growth factor with wound-adhesive and photo-crosslinkable properties.

Wound-adhesive and thermo-responsive hydrogels were prepared in an aim to develop a wound-care device for diabetic ulcers. A mixture of glycidyl methacrylated chitooligosaccharide (COS), di-acrylated Pluronic, and a recombinant human epidermal growth factor (rhEGF) formed a physical hydrogel. Photo-irradiation was subsequently applied to chemically crosslink the hydrogel. Release profiles of encapsulated rhEGF from the hydrogel showed that release rates were dependent on degradation rates of hydrogels. Human primary keratinocytes were cultivated with the released fraction from the hydrogel to measure effects of released rhEGF on in vitro differentiation of keratinocytes. Muco-adhesive property of the hydrogel was investigated in animal skins and significant amounts of quantum dot-labeled rhEGF were retained at wound sites along with chitosan. The hydrogel was administered to dorsal burn wounds in wound healing impaired animals and photo-irradiated. COS and rhEGF in the hydrogels significantly enhanced epidermal differentiation during the wound healing process. Thus, the rhEGF-encapsulated hydrogel was expected to be a potential wound care product by increasing local concentration of rhEGF at wound sites with maintaining keratinocytic differentiation.