A dual-signal mode ratiometric photoelectrochemical sensor based on voltage-resolved strategy for glucose detection

In this study, we developed a dual-signal mode ratiometric photoelectrochemical (PEC) sensor for glucose determination by using poly-(neutral red) (PNR) and ZnIn₂S₄ nanoflower as photosensitive materials. They were located at adjacent areas on one electrode substrate, in which PNR at cathode generates response signals and ZnIn₂S₄ at anode produces reference signals. By applying different bias voltages, both signals can be well separated without mutual interference. The PEC response signals for glucose were recorded by chronoamperometry, and showed a wide linear range from 0.08 mM to 30 mM (R² = 0.997) with a detection limit (S/N = 3) of 27 μM. The fabricated PEC sensor also demonstrated excellent selectivity, favorable reproducibility and long-term stability for glucose detection due to the specificity of enzyme and dual ratiometric signal mode. Moreover, this PEC ratiometric sensor was successfully used to measure glucose level in human serum samples, and the results agreed well with those from commercial glucose meter.