Generic strategy for the synthesis of highly specific Au/MIP nanozymes and their application in homogeneous assays

Abstract

Enzymes are highly complex nanomachines produced by cells with the ability to catalyse diverse chemical reactions. Their applications in biotechnology and molecular diagnostics are widespread. However, most enzymes suffer from poor operational and storage stability and high manufacturing costs. Identifying suitable enzyme for particular substrates of practical importance is often challenging. These limitations are driving the search for synthetic alternatives – nanoparticles with catalytic properties that can mimic enzymatic reactions (nanozymes). A broad variety of organic and inorganic nanoparticles have been developed with catalytic power matching that of natural enzymes. Unfortunately, developing nanozymes with substrate/ligand specificity akin to that of enzymes and antibodies has proven challenging. Here we report a novel generic strategy for the synthesis of highly specific nanozymes mimicking peroxidase based on MIP nanoparticles with gold cores, prepared by a Fenton-like reaction. Synthesis of MIP shells was achieved by localised radical polymerization of monomer mixture triggered by hydroxyl radicals produced by hydrogen peroxide decomposed on the gold surface. The products of this reaction are highly specific and robust composite Au/MIP nanoparticles (Au/MIP nanozymes) with integrated biorecognition and catalytic properties. In this work we also explore the use of synthesised Au/MIP nanozymes in oxidation of BPR by hydrogen peroxide for colorimetric detection of template analytes such as amphetamine. The developed assay allowed the detection of corresponding analytes at nanomolar concentrations in complex biological matrices. The assay was robust and easy to perform with minimal operational steps. These findings hold great promise for developing a new form of homogeneous, completely abiotic, highly sensitive, highly specific user-friendly assays for in vitro diagnostics.