Self-powered bioelectronics for peripheral nerve regeneration: Electroactive materials, energy transduction, and...

Peripheral nerve injuries remain difficult to treat because axonal regeneration is slow, incomplete, and highly dependent on timely biochemical, structural, and electrical cues. Self-powered electroceuticals offer an emerging route to deliver localized electrical stimulation with reduced dependence on bulky batteries and percutaneous leads. This review summarizes recent advances in self-powered bioelectronic systems for nerve repair, with emphasis on three representative platforms: self-electrified galvanic devices, triboelectric nanogenerators, and piezoelectric nanogenerators. From a materials and interfacial engineering perspective, we discuss how redox reactions, contact electrification, and piezoelectric polarization convert physiological or externally applied energy into therapeutic electrical outputs. Key design factors, including biodegradable metals, electroactive polymers, piezoelectric composites, conductive interfaces, encapsulation strategies, and nerve-guidance architectures, are critically examined in relation to output stability, degradation behavior, tissue compatibility, and regenerative efficacy. We further highlight preclinical evidence that self-powered electrical cues influence Schwann cell activity, axonal elongation, neurotrophic factor secretion, immune modulation, and downstream signaling pathways to enhance myelination, suppress muscle atrophy, and improve functional recovery. Finally, current limitations and future opportunities are discussed, including stimulation-dose standardization, degradation-byproduct management, scalable fabrication, closed-loop integration, and large-animal validation. This review provides a unified-materials-interface-device-biology framework for developing clinically translatable self-powered electroceuticals for nerve regeneration.