Electric Field-Driven Bacterial Membrane Disintegration with Real-Time Electrical Response in SWCNT Bioelectronic Platforms.

Abstract

We report a bioelectronic platform that integrates hydrophilically functionalized single-walled carbon nanotubes (SWCNTs) with Escherichia coli and gold (Au) electrodes to investigate real-time charge transport at microbial-electrode interfaces. Acid-functionalized SWCNTs enhance aqueous dispersibility and facilitate electron transfer in a deionized water environment under applied bias. Upon bacterial introduction, the device exhibits a sharp transient current spike followed by a stabilization phase, indicative of dynamic bacterial attachment and interfacial electron exchange. Kelvin probe force microscopy (KPFM) mapping reveals changes in contact potential difference (CPD) among the SWCNTs, bacteria, and Au electrodes, confirming localized charge redistribution. Additionally, the formation of depletion regions near electrode edges─driven by bacterial repulsion and ionic interactions, generates capacitive effects that modulate device conductivity. Systematic variation of bacterial concentration demonstrates a direct influence on device response, providing mechanistic insight into microbial charge transfer behavior. These findings establish a foundational understanding of nanobioelectronic interactions and highlight the potential of SWCNT-based platforms in real-time microbial sensing, environmental biosurveillance, and next-generation bioelectronic applications.