Development of a Process for the Spinning of Synthetic Spider Silk

TLDR

Spider silks have unique mechanical properties, yet attempts to replicate them with recombinant proteins have been unsuccessful. The study aimed to develop a single process that spins fibers with excellent and consistent mechanical properties, ultimately leading to a mechanical double‑stretch system. The process employed a mechanical double‑stretch system that independently used methanol/water and isopropanol/water mixtures to stretch the fibers. As‑spun fibers were brittle, but water dip or stretch improved their properties, and subsequent methanol or isopropanol stretching further increased strength and elongation, with methanol yielding high tensile strength and isopropanol yielding high elongation.

Abstract

Spider silks have unique mechanical properties but current efforts to duplicate those properties with recombinant proteins have been unsuccessful. This study was designed to develop a single process to spin fibers with excellent and consistent mechanical properties. As-spun fibers produced were brittle, but by stretching the fibers the mechanical properties were greatly improved. A water-dip or water-stretch further increased the strength and elongation of the synthetic spider silk fibers. Given the promising results of the water stretch, a mechanical double-stretch system was developed. Both a methanol/water mixture and an isopropanol/water mixture were independently used to stretch the fibers with this system. It was found that the methanol mixture produced fibers with high tensile strength while the isopropanol mixture produced fibers with high elongation.