Realizing high-performance glucose sensing in sweat: Synergistic use of nickel oxide nanosheets as photoelectrodes and the masking effect of Mo-POM for photoelectrochemical detection

Abstract

The detection of blood glucose plays a crucial role in clinical practice, and the innovative use of sweat as a substitute for blood has brought significant practical value in the detection of blood glucose. However, lactic acid (LA) has been found to be the main interfering substance on the detection of glucose in sweat. In this study, a photoelectrochemical sensing system was constructed by using NiO nanosheets as photosensitive materials and molybdenum-based polyoxometalate clusters (Mo-POM) as masking agents. Mo-POM, an ideal electron-capturing agent, effectively promoted the spatial separation of photo-generated charge carriers in NiO nanosheets, thereby enhancing the oxidation rate of glucose on the valence band of NiO and significantly improving the detection sensitivity. Mo-POM also exhibited the characteristics of an electron sponge, facilitating fast and reversible multi-electron transfer reactions and effectively masking certain redox substances, especially lactic acid, thus greatly enhancing the selectivity of the glucose sensor. The photoelectrochemical (PEC) sensor constructed using Mo-POM has excellent sensing capability with high sensitivity to detect glucose at a minimum concentration of 1 nM. The detection limit of the sensor is 0.33 nM (S/N = 3). This sensor can be reliably applied to the detection of glucose in sweat and the accuracy of the results was verified by gas chromatography-mass spectrometry.