A thermally and water activated shape memory gelatin physical hydrogel, with a gel point above the physiological temperature, for biomedical applications

Abstract

H-NMR spectroscopy. The degree of gelatin functionalization was found to be about 22% of the active sites according to UV-visible measurements. Hydrophilicity and swelling of gelatin were affected consequently. DSC analysis showed a significant decrease in the glass transition temperature of gelatin following UPy functionalization. Based on AFM observations, a clear micro-phase separation was induced in gelatin upon treatment. WAXS investigation showed a significant decrease in gelatin triple and single helices upon functionalization. According to rheological measurements GelUPy forms a physical network of higher stability than gelatin and a remarkable increase in elastic to viscous transition temperature from 41 °C to 83 °C was observed. GelUPy showed a clear temperature/water triggered shape memory behavior while retaining the temporary shape in the absence of these stimuli. GelUPy possesses better mechanical properties than gelatin in a wet state. Biocompatibility evaluation revealed that the viability of L929 fibroblasts remained intact on GelUPy. GelUPy, a biodegradable shape memory hydrogel, was successfully used as a controlled drug delivery matrix. Our results propose that GelUPy is a promising material in biomedical applications as a drug carrier and tissue engineering scaffold, while crosslinking with suspected toxic reagents such as glutaraldehyde is avoided.