Natural Spider Silk Nanofibrils Produced by Assembling Molecules or Disassembling Fibers

TL;DR

This study reveals the internal nanofibril structure of natural spider silk and demonstrates methods to produce similar nanofibrils through disassembly and self-assembly, advancing understanding and potential applications of silk materials.

Contribution

It provides the first complete mechanical decomposition of natural spider silk into nanofibrils and introduces self-assembly triggers for nanofibril production, enhancing fundamental understanding.

Findings

Natural silk decomposes into ~10 nm nanofibrils.

Self-assembly mechanisms can produce nanofibrils with similar morphology.

Knowledge enables silk-based high-performance material development.

Abstract

Spider silk is biocompatible, biodegradable, and rivals some of the best synthetic materials in terms of strength and toughness. Despite extensive research, comprehensive experimental evidence of the formation and morphology of its internal structure is still limited and controversially discussed. Here, we report the complete mechanical decomposition of natural silk fibers from the golden silk orb-weaver Trichonephila clavipes into ~10 nm-diameter nanofibrils, the material's apparent fundamental building blocks. Furthermore, we produced nanofibrils of virtually identical morphology by triggering an intrinsic self-assembly mechanism of the silk proteins. Independent physico-chemical fibrillation triggers were revealed, enabling fiber assembly from stored precursors "at-will". This knowledge furthers the understanding of this exceptional material's fundamentals, and ultimately, leads toward the realization of silk-based high-performance materials.