Laminin motifs inserted into a recombinantspider drag-line silk protein increase theproliferation of human dermal fibroblasts

Abstract: Spider silk is a promising biomaterial. It is highly biocompatible, non-toxic, most likely naturally degraded by the host organism over time and strong and resilient. Importantly, it consists of proteins and new motifs can relatively easily be added. While native spider silk is not possible to produce in available systems, a shorter segment of the protein, 4repCt, coding for 4 repetive alanine blocks and the C-terminal, can be inserted in vector and expressed in E-coli. Three laminin-motifs were added to 4repCt; RGD, IKVAV and YIGSR, in order to test how this affects cell proliferation of dermal fibroblasts. The results, although not confirmed with statistical certainty, strongly suggests that dermal fibroblast proliferation increase when grown on fibers with said motifs inserted compared to unmodified fiber.Fibers made with 4repCt are not as strong as native spider silk fibers. Therefore, cysteine was inserted into 4repCt, which allows production of potentially stronger fibers that can be subjected to tensile strength tests and disulphide brigde formation tests.