Biospinning by silkworms: Silk fiber matrices for tissue engineering applications

The mechanism of biospinning of natural silk fibers has been an open issue for decades. In this report a natural bio-polymeric matrix based on biospun silk fibers obtained from Antheraea mylitta, a wild non-mulberry tropical tasar silkworm, is put forward for potential applications. This report deals with the conformational transitions of silk fibroin during the biospinning process and its potential to support cell adherence and proliferation. The silk fibers obtained were aligned into linear, mixed or random patterns forming interconnected, macroporous three-dimensional matrices. The matrices were morphologically and functionally characterized with respect to fiber diameter, crystallinity, mechanical strength and biocompatibility using feline fibroblast cells. Drawn silk fibers showed enhanced stability to protease treatment in comparison with naturally occurring native gland fibroin protein. A viability assay suggested biocompatibility of these matrices in vitro. Fluorescence and confocal microscopy indicated normal cell attachment, spreading and proliferation on these biospun silk matrices. The results provided evidence for the use of biospun silk matrices as natural, inexpensive and alternative substrata for tissue engineering applications.