Living Liquid Metal Composites Embedded with Electrogenic Endospores for Next‐Generation Bioelectronics

Abstract Seamless integration of electrogenic bacteria with electronic systems represents a transformative frontier in bioelectronics. Through extracellular electron transfer, these bacteria function as both communication conduits between living systems and electronics and as dynamic electronic components with biologically driven functionality. However, conventional platforms are limited by weak biotic–abiotic interfaces, poor electrical conductivity, and inadequate mechanical and biological stability. Here, a fundamentally new class of living bioelectronic material is presented: a liquid metal composite embedded with dormant Bacillus subtilis endospores. The endospores are well integrated into the eutectic gallium–indium (EGaIn) matrix, where they facilitate the spontaneous rupture of its native oxide shell and enable sintering‐free electrical interconnectivity. This integration ultimately results in seamless biotic–abiotic interfaces and on‐demand electrogenic activation upon germination. The living composite exhibits a high baseline conductivity (≈1.1 × 10⁴ S cm −1 ), excellent self‐healing capability, operational reliability, robust patternability on diverse substrates, and long‐term biological viability. Upon spore germination, conductivity increases dramatically to 5.1 × 10⁶ S cm −1 , approaching bulk metal levels. When implemented in a microbial fuel cell, the composite functions as an active bioelectronic component, achieving a peak power density of ≈10 µW cm − 2 —significantly outperforming abiotic and nonelectrogenic counterparts. This platform pioneers a transformative strategy for advancing next‐generation bioelectronic technologies.