Nanoconfined 3D redox capacitor-based electrochemical sensor for ultrasensitive monitoring of metabolites in bacterial communication

The ability to monitor metabolites related to cell communication is important for understanding bacterial physiology, identifying bacterial species in a cellular community, and providing insights into the stage of infection. Here, we developed a nanostructured electrochemical sensor comprising a 3D-redox-capacitor-coated electrode, which was prepared by grafting a redox capacitor molecule, catechol/o-quinone, at high density to a chitosan layer. It provided high sensitivity in detecting redox-active bacterial metabolites through a redox cycling reaction in the nanoconfined structures of the electrode. We used it to monitor the secretion of signalling-related metabolites at different growth phases of Pseudomonas aeruginosa. We also used the electrode to detect signalling-related metabolites in diverse simulated body fluids mixed with P. aeruginosa culture. It was able to provide information on bacterial communication and help in sensitive diagnostic monitoring of bacterial infection.