Injectable, adhesive, self-healing and conductive hydrogels based on MXene nanosheets for spinal cord injury repair

In situ reconstruction of the micro-environment through multifunctional hydrogel verified to be an efficient strategy to accelerate spinal cord injury (SCI) repair. However, it remains great challenges to prepare hydrogel simultaneously possessing injectable, electroconductive, adhesive, and self-healing properties for the traumatic SCI repair. Herein, a novel polyvinylpyrrolidone/phytic acid/Mxenes (PVP/PA/Mxenes, PPM) hydrogel was developed for SCI repair. PVP, PA and Mxenes with appropriate content were uniformly mixed and resulted in a fast and facile gelation process. Benefiting from the reversible noncovalent interaction between PVP and PA, the obtained PPM hydrogels showed excellent shear-thinning and self-healing property, which could be implant into the irregular injured region through injection and fill the cavity without invasiveness. The incorporation of MXenes endowed the hydrogel with good electroconductive. Moreover, the PPM hydrogels exhibited good adhesion to various substrates owing to the abundant active groups distributed in the hydrogel. In vitro study further confirmed that the PPM hydrogel showed good biocompatibility. In the rat spinal cord completely truncation model, the hydrogel could significantly accelerate spinal cord regeneration by accelerating the angiogenesis, remyelination, axon regeneration and calcium channel activation, which may be through the activation of MEK/ERK signaling pathway in the regenerated spinal cord tissues. Overall, the resultant hydrogels developed in the presented work are favorable biomaterials for the repairment of traumatic SCI.