Dual dynamic bonds enable biocompatible polyurethane hydrogels with superior toughness, fatigue and puncture resistance, pH-reversibility, and room-temperature self-healability
Enhao Zheng, Peikai Zhang, Jilan Wang, Yongkang Chen, Haoxin Liu, Jing Xu, Zhaosheng Hou
Abstract
Intelligent hydrogels with remarkable mechanical properties and biocompatibility have significant potential in biomedical applications. However, preparing such hydrogels often involves a complex synthesis process, presenting a considerable challenge. This study developed a new polyurethane hydrogel (NPUG) using a simple pre-polymerization and solvent-exchange strategy through the synergistic combination of covalent acylhydrazone bond and noncovalent H-bond crosslinking. Due to the dual-crosslinked structures, the fabricated NPUG hydrogels possessed commendable tensile and compressive properties, with NPUG−III exhibiting tensile stress of 95.1 kPa, tensile elongation of 686.0 %, fracture toughness of 336.0 kJ m −3 , and compressive stress of 214.0 kPa (under 90 % compressive deformation). Meanwhile, the NPUG hydrogels displayed exceptional fatigue resistance , shape-recovery capacities, and puncture resistance as evidenced by cyclic tensile, cyclic compression, and puncture testing. The dual dynamic reversible bonds conferred the hydrogels with high self-healing efficiency (up to 97.5 % after autogenous healing at room temperature for 2.0 h) and repeated pH-responsive gel−sol transition capacities. Furthermore, cytotoxicity evaluations (cell viability >90 %) and hemolysis tests (hemolysis ratio <3.5 %) confirmed the excellent biocompatibility of the hydrogels. Hence, the dual dynamically crosslinked hydrogels, characterized by their high toughness, fatigue resistance, puncture resistance, pH-reversibility, room-temperature self-healing, and biocompatibility, represent promising candidates for various bioengineering applications.