Strong and Tough Biofibers Designed by Dual Crosslinking for Sutures

High-performance bio-based fibers have unique advantages in biocompatibility for biomedical applications, such as sutures, hernia patches, and blood vessels. Herein, strong and tough biofibers based on regenerated silk fibroins (RSFs) are designed by a dual-crosslinking strategy and prepared continuously in situ via a single-channel microfluidic device. During the wet spinning process, covalent bonds between tyrosines are introduced by photo crosslinking and coordination interactions of Zn2+ ions with serines are built between RSFs, forming a dual-crosslinked, and inter-connected network and effectively improving the mechanical performances of RSF fibers. By optimizing the wet spinning parameters and applying an optimal post-stretching treatment, dual-crosslinked RSF fibers exhibit an excellent tensile strength of 891 MPa, a remarkable Young's modulus of 15.0 GPa, a large tensile strain of 20.1%, and an outstanding toughness of 114 MJ m-3, which are superior to other regenerated biofibers. In addition to the outstanding mechanical performances, dual-crosslinked RSF fibers also possess excellent temperature adaptability, fatigue resistance, biocompatibility, and biodegradability, making them ideal candidates for biomedical applications. In vivo tests of dual-crosslinked RSF fibers as sutures demonstrate a good wound healing performance with smaller scar and lower inflammation. Strong and tough biofibers based on regenerated silk fibroins (RSFs) are designed by a dual-crosslinking strategy. Covalent bonds between tyrosines are introduced by photo crosslinking and coordination interactions of Zn2+ ions with serines are built between RSFs, forming a dual-crosslinked network. Dual-crosslinked RSF fibers exhibit excellent mechanical performances, temperature adaptability, fatigue resistance, biocompatibility and biodegradability, making them ideal candidates for sutures.image