(Invited) Closed Bipolar Electrochemistry with Multiplex Optical Readout for Rapid Diagnostics of Sepsis Syndrome Biomarkers

The combination of optical readout - fluorescence, localized surface plasmon resonance (LSPR), and absorption spectroscopy - with electrochemistry presents new avenues for the study of redox reactions, with potential for enhanced throughput, sensitivity, and spatial resolution. Here we describe a novel, dual-cell configuration for coupling high sensitivity voltammetric measurements of redox active sepsis syndrome biomarkers in an analytical cell with remote electrochemically-triggered optical reporter reactions in a reporter cell. Coupling is mediated by a mm-scale closed bipolar electrode (CBE) which communicates the local solution potential in the analyte-measuring portion of the device to an opposing reporter reaction in a remote location. Oxidation (reduction) of reversible analytes at the disk working electrode is accompanied by reduction (oxidation) on the bipolar electrode and then monitored by the accompanying oxidation of the reporter to produce a change in optical response. Applications of these optical reporter reactions for point-of-use, multiplex determinations of lactate, pyruvate, and the liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in service of developing a rapid diagnostic for sepsis syndrome will be described.