動物繊維由来タンパク質の新たな応用展開

抄録

Keratin is a fibrous protein that constitutes the intermediate filaments in epithelial cells of vertebrate animals and is a chief constituent of hair, nail, horn, and beak. A key characteristic of keratin is its amino acid composition and high cysteine content that permits the formation of many disulfide bonds. These bonds maintain a firm steric structure and make the protein water-insoluble. Keratin also contains amino acid sequences such as RGD and LDV that are involved in cell adhesion and have similarities to fibronectin, which is a known cell-adhesive protein. Thus, much like fibronectin, high cell affinity is expected for keratin if it is used as a biomaterial.
In this study keratin protein extracted from wool fibers was processed into thin film and porous sponge, in order to evaluate the potential of keratin as a scaffold material. Biodegradability of keratin substrates were evaluated by enzymatic hydrolysis using several kinds of proteases. The results of these evaluations showed keratin to have suitable biodegradability for a scaffold. The keratin materials were evaluated for their biocompatibility by culturing the structures with chondrocyte. Cells attached well and grew steadily on all of the keratin scaffold structures. The rate of cell growth on keratin was equivalent to that of the control. Keratin materials were then subcutaneously implanted in rats. Chondrocyte in the keratin substrates were well grown without eliciting a major inflammatory response.