Nanoparticles of prussian blue analogues as peroxidase mimetics for nanozyme – oxidase – based biosensors

Abstract

This work aims to develop new H2O2-sensing elements and nanozyme-oxidase-based sensors for the detection of hydrogen peroxide, glucose, and galactose. Methods. Chemical synthesis. Assay of enzymatic activity. Scanning electron microscope. Results. Hexacyanoferrates of several transient metals were synthesized and tested for their nanozymes (HCF NZs) (certificial peroxidase) activity in solution. The best representative nanozymes (NZs) were used for the construction of H2O2-sensitive sensors and nanozyme-oxidase-based biosensors. The NZs-based sensors: nAuHCF/GE and nPtHCF/GE demonstrated higher sensitivity (7.5 and 9.4-fold) than the biosensor with natural peroxidase. The developed biosensors GOX/nPtHCF/ GE and GaOx/nPtHCF/GE for the detection of glucose and galactose showed enhanced sensitivity: 900 and 540 A·M-1·m-2, respectively, broad linear range (0.02–0.2 mM). Along with a broad linear range of detection these biosensors possess low limits of detection — 4.0 μM for glucose and 6.0 μM for galactose. Additionally, these biosensors exhibited improved stability when compared to the control. Conclusions. The novelty of the presented work is related to the synthesis of new peroxidase-like NZs and the evaluation of their functionality as the chemosensors on H2O2 and as the sensing components in the oxidase-based-biosensors for assay of glucose and galactose. The nPtHCF and nAuHCF NZs exhibit high sensitivity for the target analytes, a broad linear range, and satisfactory storage stability. The main advantages of the proposed nanozyme-oxidase-based biosensors are the simple architecture of the sensing layer and the ability to operate at low working electrode potentials.