Electrochemically Accessing ROS‐Related Cytotoxicity through the Oxygen Reduction Reaction to Identify Antimicrobial Agents

Reactive oxygen species (ROS) are often believed to play a significant role in antimicrobial actions of inorganic materials. However, processes to generate ROS, in particular charge transfer routes, remain unclear and warrant further study. Building a dual-electrochemical workstation setup, herein we interpreted ROS-related cytotoxicity by monitoring oxygen reduction reactions on materials' surfaces. We found that inorganic substances can gain electrons from surrounding microbes and donate them to molecular oxygen. The cytotoxicity property is thus highly associated with materials' electrocatalytic activity and selectivity towards oxygen reduction reaction (ORR). We assessed various of inorganic substances, such as ZnO, Ag, Au, Pt, and TiO2, with results in good agreement on their apparent cytotoxicity. Our electrochemical method explored a unique route to access materials' ROS-related cytotoxicity. This will not only allow to fast screen antimicrobial agents among massive samples, but also enhance many ROS-involved applications by generating ROS on purpose.