Use of the peroxidase mimetic activity of erythrocyte-like Cu1.8S nanoparticles in the colorimetric determination of glutathione

Abstract

Erythrocyte-like copper sulfide nanoparticles (Cu_1.8S NPs) were successfully synthesized through a facile one-step solvothermal process. The as-prepared Cu_1.8S NPs exhibited localized surface plasmon resonance in the near-infrared region due to their copper deficiency, which resulted in excellent peroxidase mimetic properties. The Cu_1.8S NPs were able to catalyse tetramethyl benzidine to its blue oxidized product in the presence of H₂O₂ following the Fenton reaction. Glutathione inhibited the peroxidase-like activity of Cu_1.8S NPs by scavenging the reactive oxygen species produced in the Cu_1.8S–H₂O₂ system. Thus a colorimetric sensing platform for glutathione was established with a linear range of 0.5–10 mM and a limit of detection of 0.06 mM based on the peroxidase mimetic activity of erythrocyte-like Cu_1.8S NPs. The array was successfully used for the determination of glutathione in commercial pharmaceutical tablets.