Evaluation as biomaterials of silk fibroin degummed by different method

Abstract

Non-woven fabrics made of two kinds of silk fibroin, one extracted directly from silk glands of living silkworms (silk grand fibroin; SGF) and the other regenerated from degummed silk fibroin (regenerated silk fibroin; RSF), were prepared. The secondary structure, mechanical properties and histological characters of these two kinds of fabrics were investigated and compared for biomaterial use. Although the ¢-sheet crystal contents of these two kinds of fabrics were the same, the breaking strength and the Young's modulus values of SGF fabric were significantly higher than those of RSF fabric. The difference of the physical properties is considered to be derived from the difference of the molecular weights of the silk fibroins because RSF degrades during the degumming process. In the histological test, SGF fabrics didn't show calcification, but phagocytosis by multinucleated giant cells was partly observed 4weeks after the implantation into subcutaneous mouse tissue. Expression level of cytokines from in vitro tests revealed that inflammation by macrophages is the same in SGF and RSF films.