Utilization of Peroxide Reduction Reaction at Air-Liquid-Solid Joint Interfaces for Reliable Sensing System Construction.

The utilization of hydrogen peroxide (H2 O2 ) cathodic reaction is an ideal approach to develop reliable biosensors that are immune to interferences arising from oxidizable endogenous/exogenous species in biological solutions. However, practical application of such a detection scheme is limited due to the significantly fluctuating oxygen levels in solutions, as oxygen can be reduced at similar potentials. Herein, this limitation is addressed by developing a novel electrode system with superhydrophobicity-mediated air-liquid-solid joint interfaces, which allows the rapid and continuous transport of oxygen from the air phase to the electrode surface and provides a fixed interfacial oxygen concentration. Using cathodic measurement of the enzymatic product H2 O2 , the sensing platform is applied to detect glucose, a model analyte, achieving a remarkably high selectivity (≈2% signal modulation due to common biologic interferents), sensitivity (18.56 µA cm-2 mm-1 ), and a dynamic linear range up to 80 × 10-3 m. The utility of H2 O2 reduction reaction at triphase interface to achieve reliable sensing platforms is general, and hence has broad potential in the fields of medical research, clinical diagnosis, and environmental analysis.