Magnet-oriented hydrogels with mechanical–electrical anisotropy and photothermal antibacterial properties for wound repair and monitoring

For hydrogel wound dressings, it remains a great challenge to simultaneously achieve multifunctional hydrogels with wound-matching mechanical performance, antibacterial activity and monitoring capability for the integration of treatment and rehabilitation training monitoring during wound repair. Inspired by the highly ordered hierarchical structures of natural soft tissues, ordered magnetoelectric nanosheet structures are introduced into gelatin-oxidized dextran (Gel-ODex) hydrogels to endow the hydrogel with anisotropy and versatility in this study. First, magnetoelectric nanosheets (Fe3O4-PDA-rGO, MPG) containing polydopamine (PDA) were obtained by dopamine (DA)-mediated formation of Fe3O4 nanoparticles in situ on the surface of reduced graphene oxide (rGO). Then, anisotropic Gel-ODex-MPG (GOH-MPG) hydrogels were prepared by introducing MPG into the Gel-ODex hydrogel network under a magnetic field. The GOH-MPG hydrogel exhibited anisotropic mechanical and conductive properties and great photothermal antibacterial performance under near-infrared light (NIR, 808 nm). In addition, the anisotropic GOH-MPG conductive hydrogel could accelerate infected wound healing and sensitively detect human movements, which is helpful for monitoring the wound status and for rehabilitation training during wound recovery. To the best of our knowledge, this was the first exploration of the combination of anisotropic hydrogels in the field of wound therapy and wearable sensors, which sheds light on developing anisotropic hydrogels with multifunctionality in tissue repair and personal health monitoring to realize the integration of treatment and rehabilitation training monitoring.