Noncovalent Muscle-Inspired Hydrogel with Rapid Recovery and Antifatigue Property under Cyclic Stress.

Designing muscle-inspired hydrogels that possess structure and bioactivity similar to muscles is an eternal pursuit in material sciences and tissue engineering. However, the development of a muscle-inspired hydrogel via the formation of noncovalent interactions remains challenging, and its application in sustained loading situations such as cyclic stresses is limited. Herein, H-bonds and microcrystalline domains were introduced, and a noncovalent muscle-inspired hydrogel was developed to mimic both the physical structure and functionality of muscles at the macroscopic level. The hydrogel exhibited excellent mechanical properties (a fracture strength of 2.16 ± 0.08 MPa, fracture strain of 830 ± 23%, elastic modulus of 275 ± 9 KPa, and toughness of 7.04 ± 0.80 MJ/m), a large energy dissipation (2.00 ± 0.27 MJ/m at 600% elongation), and a rapid self-recovery (92 ± 1% toughness recovery within 20 min). Antifatigue behavior of the muscle-inspired hydrogel was observed upon successive tensile and compressive cyclic loadings. Under 100 cycles of loadings, the robustness of the hydrogel has been maintained and even improved, which are achieved due to strain-induced orientation. Furthermore, the hydrogel was found to be self-healed. This hydrogel promises to be among the most relevant drivers for the development of new-generation muscle-inspired hydrogels in the next decade.