Spontaneously N‐Doped Conjugated Polyelectrolyte Coatings Accelerate Electron Uptake in <i>Shewanella Oneidensis</i>

Bioelectrochemical systems interconvert electrical and chemical energy using living microorganisms, but their efficiency remains limited by slow electron exchange across abiotic-biotic interfaces. Herein, a spontaneous n-doped water-dispersible conjugated polyelectrolyte (CPE), PNB, is developed. The CPE self-assembles on the surface of Shewanella oneidensis MR-1 to create biocompatible coatings that accelerate inward extracellular electron transfer. PNB is obtained via an aldol condensation reaction and is described by an acceptor-acceptor π-conjugated backbone bearing quaternary ammonium side chains. This molecular architecture enables stable n-doping in aqueous media and a broad reduction potential window. When integrated as a cathodic interlayer, PNB-S. oneidensis biohybrids exhibit a 14-fold enhancement in electron injection and a 4-fold increase in electro-driven succinate production, compared to unmodified cells. Single-cell electrochemical mapping confirms faster, more efficient per-cell electron influx. These findings demonstrate that n-type CPEs can bridge external electrodes with cellular metabolisms, opening a material-based route to high-performance bioelectronic and electrosynthetic systems. By enabling more facile charge transfer between synthetic semiconductors and living catalysts, this work establishes a soft materials-driven framework for designing electronically coupled microbial systems with potential to advance sustainable bioelectronic technologies.