Fabrication and biological evaluation in vivo of an injectable keratin hydrogel as filler materials

Abstract

Filler materials of soft tissue should have good biodegradable absorption and biocompatibility. To investigate feasibility of keratin hydrogels used as filler materials, a keratin with high molecular weight and self-assembly ability was extracted from human hair using a modified reduction method and was characterized using sodium dodecyl sulfate–polyacrylamide gel electrophoresis, Fourier transform infrared, and X-ray diffraction. An injectable keratin hydrogel was also prepared and its water absorption, cell toxicity, and histological behavior were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method and subcutaneously implanted experiment. The results showed that the modified extraction method could keep the activity of the keratin and provided the self-assembly crosslinked ability of the keratin. The water absorption of the keratin hydrogel could be controlled by adjusting some preparation parameters and the percentage of water absorption was up to 850%. In addition, the subcutaneous injection experiment for Sprague Dawley rats indicated that the keratin hydrogel had good biocompatibility and could promote the formation of angiogenesis as well as proliferation. It can be predicted that the keratin extracted from human hair and keratin hydrogel have good application prospects in the field of filler materials for soft tissue.