A photoelectrochemical glucose sensor based on gold nanoparticles as a mimic enzyme of glucose oxidase

This work reports the first construction of the ternary layers of ITO/PbS/SiO₂/AuNPs nanostructure for development of photoelectrochemical (PEC) glucose sensor. Herein, the thioglycolic acid-capped PbS quantum dots was employed as a PEC active probe, which is very sensitive to oxygen. The small gold nanoparticles (AuNPs) were act as nanozyme (mimic enzyme of glucose oxidase) to catalytically oxidize glucose in the presence of oxygen, meanwhile consumed oxygen and then resulted in the decrease of cathodic photocurrent. The insertion layer of SiO₂ nanoparticles between PbS and AuNPs could reduce efficiently the base current due to its low electroconductivity, which improved the detection limit. The proposed PEC sensor exhibited high sensitivity and gold selectivity towards glucose. The linear response of glucose concentrations ranged from 1.0 μM to 1.0 mM with detection limit of 0.46 μM (S/N = 3). The results suggest the potential of design and development of numerous nanozyme-based PEC biosensors with the advantage of the simplicity, stability, and efficiency.