Preparation of gelatin/poly (γ-glutamic acid) hydrogels with stimulated response by hot-pressing preassembly and radiation crosslinking.

The conventional preparation method of natural polymers is low in strength, which limits the application of multi stimuli responsive hydrogels as intelligent wound dressings. In this work, interpenetrating gelatin and γ-polyglutamic acid (γ-PGA) hydrogels with good biocompatibility, biodegradability and mechanical properties were prepared by hot-pressing pre-gelation of gelatin/γ-PGA and synergistic with gamma irradiation. The effects of radiation crosslinking dosage on gel fraction, swelling ratio, tensile strength and surface morphology were investigated. The biocompatibility of radiation cross-linked hydrogel was evaluated by aseptic test, hemolysis test, cytotoxicity test, delayed hypersensitivity reaction as well as in vivo degradation studies from in vitro to in vivo. The optimized hydrogel irradiated by 25 kGy has good water retention and biodegradability, especially the stimulation of temperature, pH value, salt species and concentration. The mechanical strength, biocompatibility and responsive properties of the hydrogel indicate that the intelligent hydrogel prepared by this method is a good hydrogel biomaterial for developing interactive wound dressing.