Rational Design of Three-in-One Pt/MnO2/GO Hybrid Nanozyme with Enhanced Oxidase Mimic Performance for Colorimetric Detection of Ascorbic Acid and Cysteine

Abstract

In this work, a novel three-in-one Pt/MnO2/GO hybrid nanozyme with wide pH and temperature working range was rational designed using simple hydrothermal and reduction strategy. The fabricated Pt/MnO2/GO displayed enhanced oxidase like activity than single active component owing to the excellent conductivity of GO, increase active sites and electron transfer capacity, synergistic effect between each component and decrease in binding energy for adsorbed intermediates. Combing chemical characterization and theoretical simulation calculations, the O2 reduction process over Pt/MnO2/GO nanozyme and the generated reactive oxygen species in the nanozyme-TMB system were thoroughly illustrated. Based on the excellent oxidase mimic property of Pt/MnO2/GO nanozyme, a colorimetric strategy was proposed to detect the ascorbic acid (AA) and cysteine (Cys), and the experimental results indicate that this assay method could quantify the AA and Cys with high accuracy and selectivity. Good recoveries were achieved in the human serum and fresh fruit juice detection procedures, demonstrating the potential applications of Pt/MnO2/GO-based colorimetric strategy in complex biological and food matrix.

Keywords: nanozymes, Pt/MnO2/GO, ascorbic acid, Cysteine, Mechanism