Fenton reaction-mediated fluorescence quenching of N-acetyl-l-cysteine-protected gold nanoclusters: analytical applications of hydrogen peroxide, glucose, and catalase detection

Abstract

Given the importance of hydrogen peroxide (H₂O₂) in many biological processes and its wide application in various industries, the demand for sensitive, accurate, and economical H₂O₂ sensors is high. In this study, we used Fenton reaction-stimulated fluorescence quenching of N-acetyl-L-cysteine-protected gold nanoclusters (NAC-AuNCs) as a reporter system for the determination of H₂O₂. After the experimental conditions were optimized, the sensing platform enabled the analysis of H₂O₂ with a limit of detection (LOD) as low as 0.027 μM. As the glucose oxidase cascade leads to the generation of H₂O₂ and catalase catalyzes the decomposition of H₂O₂, these two biocatalytic procedures can be probed by the Fenton reaction-mediated quenching of NAC-AuNCs. The LOD for glucose was found to be 0.18 μM, and the linear range was 0.39–27.22 μM. The LOD for catalase was 0.002 U mL⁻¹, and the linear range was 0.01–0.3 U mL⁻¹. Moreover, the proposed sensing methods were successfully applied for human serum glucose detection and the non-invasive determination of catalase activity in human saliva, demonstrating their great potential for practical applications.