Structural and rheological properties of methacrylamide modified gelatin hydrogels.

Dynamic shear oscillation measurements at small strain were used to characterize the viscoelastic properties and related differences in the molecular structure of hydrogels based on gelatin methacrylamide. Gelatin was derivatized with methacrylamide side groups and was subsequently cross-linked by radical polymerization via photoinitiation. The light treatment of methacrylamide gelatin solutions resulted in the production of hydrogel films with high storage modulus (G').

In vitro and in vivo biocompatibility of dextran dialdehyde cross-linked gelatin hydrogel films.

The biosafety of a new hydrogel wound dressing material consisting of dextran dialdehyde cross-linked gelatin was evaluated (i) in vitro in cultures of dermal fibroblasts, epidermal keratinocytes, and endothelial cells, three cell types which play a major role in the process of cutaneous wound healing, and (ii) in vivo by subcutaneous implantation studies in mice. The cytotoxicities of this hydrogel, two semi-occlusive polyurethane dressings (Tegaderm and OpSite), and a hydrocolloid dressing (DuoDERM) were compared by measuring cell survival with the tetrazolium salt reduction (MTT) assay after incubations of the wound dressing samples for up to 6 d, in the presence of--but not in direct contact with--the cells. In vitro, the degree of cytotoxicity of the new hydrogel was greater in keratinocyte cultures than in fibroblast and endothelial cell cultures, and increased upon longer incubation time.

In vitro release characteristics of bioactive molecules from dextran dialdehyde cross-linked gelatin hydrogel films.

Hydrogel films, prepared by cross-linking of gelatin with dextran dialdehydes (weight ratio 2:1), and containing either fluorescein isothiocyanate dextran (Mw 70000) or polypeptides were evaluated in terms of their release characteristics and mechanical properties upon increasing storage time at 4 degrees C. Important changes in release kinetics and mechanical properties of the cross-linked gelatin films were observed, especially during the first week after the hydrogel production. Rheological and NMR measurements showed that the mechanical properties of the gelatin hydrogel films were improved with increasing storage time.