The Steadfast Au@Pt Soldier: Peroxide-Tolerant Nanozyme for Signal Enhancement in Lateral Flow Immunoassay of Peroxidase-Containing Samples

The approach to inhibit endogenous peroxidases by elevated concentrations of hydrogen peroxide while maintaining the high peroxidase-mimicking activity of Au@Pt nanozymes was developed. The approach facilitates selective and highly-sensitive detection of peroxidase-mimicking nanozyme nanozymes in the background of endogenous peroxidases. Au@Pt nanozyme was used as the colorimetric and catalytic label in lateral flow immunoassay of an important plant pathogen – potato virus X. The inhibition of endogenous peroxidases in plant extracts and selective detection of Au@Pt nanozyme provides the lowest limit of detection among immunochemical assays of potato virus X (up to 500 times lower compared to the assay with conventional gold nanoparticles). The proposed approach uses the fundamental principle of enzyme inhibition by the substrate. It is universal and applicable to all matrixes with peroxidase activity.