Mechanoadaptive nanowire viscoplastic composites with strain-enhanced conductivity for reprocessable bioelectronic interfaces.

Bioelectronic interfaces must mechanically conform and adapt to biological tissues while maintaining stable electrical performance during motion and deformation. Existing soft conductors, however, often couple mechanical strain to electrical resistance, accumulate interfacial stress, and hinder reprocessing. Here, we report nanowire viscoplastic composites that combine silver nanowires with a dynamically crosslinked, short-chain polyborosiloxane matrix to produce emergent electromechanical behavior. The viscoplastic matrix permits deformation-induced nanowire reorganization, yielding high conductivity enhanced with strains. It also imparts fast stress relaxation, controllable yielding, and plastic conformability, enabling stress-free, mechanoadaptive contact with biological tissues. The material is self-healing, reconfigurable, and solvent-processable for recycling. It forms stable adhesion across porcine, rat, and human skin; accommodates hair regrowth; and exhibits excellent cytocompatibility and antibacterial function. As dry electrodes, these composites exhibit low impedance and resolve perilaryngeal muscle fatigue through high-resolution surface electromyography in humans. This work expands the materials design space for bioelectronic interfaces.