Micro-Nanoengineered Carbon Nanotube Electrodes with Ionic Liquid Interfaces for Efficient Pathogen Inactivation and Detection

Efficient, low-energy, and byproduct-free strategies for pathogen inactivation and monitoring are urgently needed for water, air, and food safety. Here, we report an integrated nanoelectrochemical platform that combines ultralow-voltage pathogen inactivation with real-time biosensing. A nanoscale Pt/Ti-carbon nanotube (CNT)-Au/Ti three-electrode device is fabricated via high-precision micro- and nanomanufacturing, in which a networked CNT film serves as both the conductive substrate and the electroactive interface. Trace amounts of a hydrophobic ionic liquid are immobilized within the CNT network, forming a stable CNT/ionic liquid/aqueous three-phase interface that promotes efficient single- and multielectron oxygen-reduction pathways and the in situ generation of reactive oxygen species. As a result, complete electrocatalytic inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is achieved at concentrations up to 10⁹ CFU/mL using an applied potential of only -0.6 V (vs a built-in quasi-reference) and a low current density of 0.1 mA cm⁻². Concurrently, the platform functions as a sensitive bacterial sensor, in which changes in the reduction features of cyclic voltammetry enable quantitative detection of E. coli over a linear range of 0-10⁷ CFU/mL with good reproducibility. This work establishes a general strategy for constructing multifunctional nanoelectrochemical systems and provides a practical route toward integrated pathogen inactivation and monitoring technologies.