Self-Healing Electrogenic Living Hydrogels for Durable Bioelectronics

Living conductive hydrogels that unite biological activity with robust electrogenic performance are emerging as transformative platforms for adaptive bioelectronics, yet most lose electrical functionality after mechanical damage or extended use. Here, we introduce an electrogenic living hydrogel embedding Bacillus subtilis spores─metabolically dormant, environmentally resilient, and capable of germinating into electrogenic bacteria─within a dual self-healing framework. The primary mechanism exploits hydrogen-bonded poly(3,4-ethylenedioxythiophene):polystyrenesulfonate-poly(vinyl alcohol) (PEDOT:PSS-PVA) networks to restore mechanical integrity, while a secondary, conductivity-specific mechanism is activated by rupture of carbon nanotube (CNT)-loaded cellulose acetate microcapsules at the fracture interface, re-establishing percolation pathways. Germination triggers extracellular electron transfer (EET) by B. subtilis, synergistically boosting conductivity beyond the undamaged state and reducing internal resistances. As a proof-of-concept, the hydrogel served as the anode in a paper-based microbial fuel cell (MFC), achieving a maximum power density of 1.5 μW cm^-2 and an open-circuit voltage of 0.38 V─comparable to state-of-the-art paper MFCs. By integrating mechanically resilient matrices, microcapsule-mediated conductivity restoration, and biologically triggered electroactivity, this platform establishes a paradigm for self-repairing, high-performance living electronics with broad potential in biosensing, energy harvesting, and soft bioelectronic systems.