Injectable and Cytocompatible Dual Cross-Linking Hydrogels with Enhanced Mechanical Strength and Stability

Injectable hydrogels have become increasingly important in the fields of tissue engineering and drug delivery. However, their biological applications are greatly limited by the weak mechanics and poor stability under a physiological environment. Herein, we developed a stable, strong, and injectable hydrogel by linking strong micelle cross-linking with tetra-armed PEG. This dual cross-linking strategy has not only made hydrogels nonswelling but also maintained the relative integrity of the gel network during the degradation process, both of which work together to ensure the mechanical strength and stability of our hydrogel under a physiological environment. A compressive stress of 40 MPa was achieved at 95% strain, and the mechanical properties could remain stable even after immersion into a physiological environment for two months. Besides, it also showed outstanding antifatigue properties, good tissue adhesion, and good cytocompatibility. On the basis of these characteristics, these dual cross-linking injectable hydrogels would find appealing application in biomedicine especially for the repair of load-bearing soft tissues.