Carboxylic-group-functionalized single-walled carbon nanohorns as peroxidase mimetics and their application to glucose detection

Abstract

Carboxylic-group-functionalized single-walled carbon nanohorns (SWCNHs-COOH) have been found to possess peroxidase-like activity for the first time. Similar to natural peroxidase, SWCNHs-COOH can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine by H₂O₂ to produce a blue color solution. Compared with horseradish peroxidase, SWCNHs-COOH exhibit higher activity and stability under harsh reaction conditions. The catalytic activity of SWCNHs-COOH depends on the concentration of H₂O₂. A colorimetric method for glucose detection was developed by combining the SWCNH-COOH catalytic reaction and the generation of H₂O₂ by the enzymatic oxidation of glucose with glucose oxidase. Taking into account the advantages of good stability, high biocompatibility in aqueous solutions, being metal-catalyst free, and high purity, SWCNHs-COOH are expected to have potential applications in biotechnology and clinical diagnostics as enzymatic mimics.