Major ampullate spidroin proteins 1 and 2 (MaSp 1 and MaSp 2) of dragline spider silk were obtained from Dr. Randolph V. Lewis of Utah State University. These proteins were purified from the milk of transgenic goats and mixed at a MaSp1/MaSp2 ratio of 4:1 to obtain optimized mechanical properties [31 (link)]. While most of the study was done using spider silk (SS) proteins, silkworm silk (SWS) and collagen (COL) were used for comparison and demonstrating their competence as alternative materials. Silkworm silk fibroin was extracted from cocoons of Bombyx mori silkworms (Aurora Silk, Portland, OR) and purified as per the earlier published protocol [32 (link), 33 (link)]. COLI from calfskin was purchased from MP Biomedicals (Solon, OH). For electrospinning, the proteins were dissolved in 1,1,1,3,3,3-hexafluoro–2-propanol (HFIP) (Fisher Scientific, Pittsburgh, PA).
High purity single-walled CNTs were purchased from HELIX Material Solution (Richardson, TX), and were oxidized following the previously published protocol [27 (link), 29 (link)]. A minute quantity of oxidized SWCNT was added to SS, SWS or collagen solution for electrospinning to generate protein-CNT composite fibers.
High purity single-walled CNTs were purchased from HELIX Material Solution (Richardson, TX), and were oxidized following the previously published protocol [27 (link), 29 (link)]. A minute quantity of oxidized SWCNT was added to SS, SWS or collagen solution for electrospinning to generate protein-CNT composite fibers.