Construction of a peroxidase nanozyme based on Prussian blue and its application in GSH colorimetric assays

Abstract

Nanozymes demonstrate significant potential for various applications in multiple fields due to their mimetic activity, stability, ease of storage, and cost-effectiveness compared to natural enzymes. Prussian blue nanoparticles (PB NPs) exhibit exceptional catalytic activity and have a favorable preparation process, making them valuable substitutes for peroxide-mimetic enzymes. However, their utilization in colorimetric sensing is limited due to the inadequate stability of individual PB nanoparticles, tendency to aggregate in aqueous solutions, demanding purification conditions, and inherent color interference. In this study, we prepared and characterized a Prussian blue nanocomposite, mSiO₂@PB, which possesses a well-dispersed aqueous solution and eliminates the interference caused by its own color. Additionally, the mSiO₂@PB nanocomposite displayed excellent peroxidase-like activity and facilitated the color development reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂. By leveraging the inhibitory effect of glutathione (GSH) on the oxidation of TMB, we constructed a sensitive biosensing platform for the colorimetric detection of GSH in physiological fluids. Furthermore, this study developed a portable analysis method for GSH detection using smartphones as detection terminals, capitalizing on their photo and colorimetric analysis capabilities. In conclusion, our work establishes an effective platform for the detection of GSH in physiological body fluids, thereby expanding its potential applications in biomedical analysis and monitoring.