Bioinspired polypeptide as building blocks for multifunctional material design

Abstract The exceptional mechanical properties of spider silks from their extraordinary natural design make them outstanding biomaterial candidates. Herein, inspired by the outer egg sac silk from Nephila pilipes, we introduce a gradient of recombinant biomimetic polypeptides (BMPPs) through a semi-rational design. The synthesized BMPPs show good water solubility with dynamic conformations of random coil/helix. Both biomimetic nanofiber membranes and macrofiber yarns are fabricated using BMPPs as blend with polycaprolactone (PCL) through electrospinning. The resulting nanofiber membrane yields almost double tensile strength (22.7 ± 3.3 MPa) compared to that of PCL (12.5 ± 1.4 MPa), without sacrifice of toughness. The as-fabricated microfiber yarns could accommodate both improvement of tensile strength (208 ± 8.3 MPa, almost twice of PCL value) and toughness (163 ±13 MJ/m3, more than twice of PCL value), suggesting the crosslink role of BMPP in PCL network. By fusion of cell-binding domains in the BMPP, the materials also illustrate great potentials into new biomedical materials.