Dual-mode colorimetric and photothermal sensing platform for point-of-care testing of uric acid based on enhanced peroxidase-like activity of platinum-based nanozyme by adenosine triphosphate.

Abstract

To break through the limitation of low peroxidase-like (POD-like) activity of conventional nanozymes at neutral pH, platinum-based nanozyme assisting with adenosine triphosphate (Pt NZ/ATP) system is prepared in this study. ATP enables to promote the stability of Pt NZ and the production of O2•- and •OH, and Pt NZ/ATP displays remarkably enhanced POD-like activity (Michaelis constant Km 0.46 mM) than only Pt NZ (Km 2.1 mM). Uric acid (UA) reacts with urate oxidase to form H2O2. Then, Pt NZ/ATP triggers the POD-like reaction to catalyze H2O2 to oxidize 2,2-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) into ABTS•+, which shows broad absorbance spectrum in visible (obvious color change) and near-infrared (high photothermal conversion efficiency) regions. Thus, dual-mode colorimetric and photothermal platform for point-of-care testing (POCT) of UA with smartphone camera and thermometer were constructed with linear range of 1.5 to 70 μM, and limit of detection of 0.81 and 1.05 μM, respectively. The relative standard deviations were less than 9.10% and 9.90% in human serum samples, and relative errors were lower than 8.28% and 6.93% comparing to the results of biochemical detector, respectively. This work not only provides an efficient enhancement approach for nanozyme activity, but also establishes sensitive, accurate and portable dual-mode POCT platform for UA assay.