Bioinspired Silk Fiber Spinning System via Automated Track-Drawing

Regenerated silk fibroin (SF) fiber is a multifaceted protein matrix suitable for engineering a wide variety of biological materials. Numerous artificial spinning systems have been developed to mimic the molecular structure and hierarchical properties found in native silks. Here, we show a bioinspired technique that can readily form nanofibers and induce both orientation and structure formation of crystalline beta-sheet assemblies seen in natural silk. In this study, electrospun postdrawn SF nanofibers were fabricated using an automated track-drawing (TD) approach for the continuous production of highly aligned protein nanofibers. This one-step postdrawing process simulates the dominant pulling force seen in natural spinning. The mechanical performance of the postdrawn SF nanofibers with a draw ratio of 2 (DR2) via TD exhibited a 115% increase in Young's modulus and an 80% increase in ultimate tensile strength, compared with the undrawn SF fibers after water treatment. It was also determined that the intermolecular beta-sheet content in DR2 nanofibers increased by 75%. This contribution led to higher glass-transition and degradation temperatures. These biomimetic fibers with structural hierarchy and mechanical properties may be used to build high-performance load-bearing and directionally propagating structures relevant in biomaterial and sustainable material applications.

Automated summary

Regenerated silk fibroin fibers produced through bioinspired techniques exhibit highly aligned structures and superior mechanical properties, making them suitable for applications in biomaterials and sustainable materials.