Biological fibers based on naturally sourced proteins: mechanical investigation and applications

Biological protein-based fibers are widely investigated in biological and biomedical fields owing to their advantages of lightweight, strong mechanical performance, biodegradability, and biocompatibility. So far, the mass production of natural protein-based silks is restricted by the limited sources and high cost. To fabricate high-performance fibers, it is highly desired to introduce cheap and easily available proteins and to develop advanced spinning technology. Recent progress in the design and fabrication of naturally sourced protein fibers is outlined here. According to the types of naturally sourced proteins, fibrous and globular protein-based fibers are discussed. In addition, the structure and fiber mechanical performance on the basis of different types of widely available proteins are reviewed in detail. With the developed spinning techniques, both fibrous and globular protein-based fibers could achieve outstanding mechanical performance or even surpass natural silks, showing potential biomedical applications. Finally, a perspective on further development of biological protein fibers is highlighted.