Electrospun Recombinant Spider Silk Proteins for Tissue Engineering Scaffolds

As a potential next-generation biomaterial, spider silk's durability, elasticity and biocompatibility make it suitable for a wide range of medical applications. In this study, we developed tissue engineering scaffolds from recombinant spider silk proteins derived from the dragline silk of Nephilia clavipes, a golden orb weaving spider.  This silk is composed of two proteins, the major ampullate spidroin proteins (MaSp) #1 and #2.  In our studies, thin recombinant MaSp2 protein films were first studied to determine surface properties and cell-material interactions.  Synthetically spun fiber mats were then developed using an electrospinning process in which MaSp2 was dissolved in 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP).  The mechanical properties of the electrospun mats were characterized with varying process adjustments, including spin dope concentration. Biological studies included the incorporation of antibiotics into the fiber scaffolds to inhibit bacterial growth.  Unmodified fiber mats demonstrated little cell attachment and the inhibition of cell growth, so in order to improve mammalian cell attachment and growth on the fibers, the material was modified covalently with the cell binding peptide, RGDS.  The modified scaffolds demonstrated cell growth to confluence of both NIH-3T3 fibroblasts as well as human skin fibroblasts.