Dynamic Bond-Mediated Self-Adaptive Injectable Conductive Hydrogels for Peripheral Nerve Regeneration

Injectable conductive hydrogels show promise for peripheral nerve regeneration. However, a trade-off exists between mechanical adaptability and stable electrical conductivity, limiting their therapeutic effectiveness. To overcome this limitation, a self-adaptive injectable hydrogel (AuSeGD) was developed. It features a hierarchical dynamic network comprising weak diselenide (Se-Se) bonds and strong gold-selenium (Au-Se) coordination bonds. The Se-Se bonds dissipate mechanical stress, while the Au-Se bonds maintain the integrity of the conductive framework. AuSeGD is created through UV-initiated polymerization of methacrylated gelatin, a diselenide-containing crosslinker, and gold nanoparticles. It exhibits shear-thinning injectability, rapid self-healing, moderate tissue adhesion, and stable electrical conductivity under repeated mechanical loading. In vitro studies demonstrate support for Schwann cell viability and excellent hemocompatibility. In a rat sciatic nerve crush injury model, AuSeGD forms an integrated electroactive bridge, accelerating axonal regeneration and remyelination. This is evidenced by increased expression of neurofilament and myelin basic protein, thicker myelin sheaths, and an optimized G-ratio. The structural repair leads to motor functional recovery, improving the sciatic function index and reducing gastrocnemius muscle atrophy. This bond strategy effectively balances adaptability and conductivity, offering a versatile material platform for electroactive biomaterials in complex tissue repair.