Physical-chemical double crosslinked silk fibroin hydrogel for high-performance bone screws.

Hydrogels are widely used due to their exceptional biocompatibility and adaptability, but their weak mechanical properties limit their application in biomedical engineering. Herein, we rapidly attained a comprehensive enhancement of silk fibroin hydrogels in mechanical properties by employing a physical-chemical double crosslinking strategy. The SF was ultrasonicated and simultaneously photo-crosslinked to form a di-tyrosine network interspersed with β-sheet blocks, resulting in a SF hydrogel network structure with both rigid and flexible domains. The SF hydrogels exhibited a maximum breaking strength of 59.7 kPa and a Young's modulus of 82.2 MPa, demonstrating significant rigidity and flexibility. Subsequently, the silk screws prepared by this double crosslinking strategy showed extraordinary compressive strength and Young's modulus of 41.8 MPa and 10.9 MPa, respectively. The silk screws cocultured with osteoblasts showed optimal biocompatibility, and the rate of biodegradation could be matched to the rate of osteogenesis. The screw also exhibited high adaptability in the requirements of bone screws. In this study, the SF hydrogels prepared by physical-chemical double crosslinking have extraordinary mechanical properties and biocompatibility, which provides a new avenue for the preparation of high-performance hydrogels and has great potential in bone tissue engineering.