An Au@CuS@CuO2 nanoplatform with peroxidase mimetic activity and self-supply H2O2 properties for SERS detection of GSH

Abstract

The abnormal fluctuations of glutathione (GSH) in vivo often reflect disease progression and are closely linked to human metabolism and physiological functions. Highly sensitive and selective detection of GSH is crucial for guiding early diagnosis and treatment; however, achieving this remains a significant challenge. In this study, we developed an enzyme activity sensor platform for the efficient detection of GSH. This platform utilizes Au@CuS core–shell materials loaded with CuO₂ nanoparticles to create a composite nanosensor system. Under slightly acidic conditions, CuO₂ on the nanomaterial’s surface decomposes into H₂O₂ and Cu²⁺ ions. The generated H₂O₂ then reacts with tetramethylbenzidine (TMB) in the presence of peroxidase-like CuS to yield oxidized tetramethylbiphenyl (_OXTMB), which generates a distinctive Raman signal. Upon addition of GSH to the system, the unique _OXTMB signal diminishes due to GSH’s strong antioxidant capacity and the consequent consumption of _OXTMB. This sensing method enables sensitive detection of GSH, with a detection limit as low as 1.2 × 10^-13 mol∙L^-1. This approach holds promise for providing researchers with rapid and precise in vitro analysis of GSH, serving as an indicator for early disease diagnosis and real-time evaluation of treatment efficacy.