Fig. 5: Mechanical properties of selected biomimetic protein fibers.

Mimicking natural protein fiber production can imply either the used protein, the establishment of a spinning solution, or the spinning process, or any combination thereof. a Regenerated B. mori fibroin biomimetically spun using dry-spinning, resulted in µm-sized fibers with a tensile stress of ~250 MPa. Adapted and modified with permission from ref. ¹³³, copyright American Chemical Society, 2016. b In terms of spider silk, recombinant proteins mimicking the natural ones have been processed into a biomimetic spinning dope (BSD) based on native-like liquid-liquid phase separation. In addition, classical spinning dopes (CSD) were prepared by dehydration using polyethylene glycol (PEG). The dopes were then spun using a microfluidic set-up inspired by the natural spinning process (including pH shift, elongational flow and ion exchange), resulting in um-sized fibers with a maximum stress of ~420 MPa. Adapted and modified with permission from ref. ¹³⁶, copyright American Chemical Society, 2023. c Spinning solutions of keratin were formed by coacervation, and the wet-spinning process involves ion exchange and a pH drop. The mimicry of the different natural factors like the spinning solution as well as the spinning conditions are resulting in micrometer scale fibers with excellent mechanical properties. Adapted and modified with permission from ref. ¹³⁷, licensed under CC BY 4.0. d Collagen was extracted from natural sources like rat-tail, solved under acidic conditions, and spun using a microfluidic-spinning process, resulting in fibers with a diameter of 3.6 µm and a tensile strength of 284 MPa. Adapted and modified with permission from ref. ⁹¹, copyright American Chemical Society, 2016.