Colorimetric and photothermal dual-mode immunosensor based on Ti3C2Tx/AuNPs nanocomposite with enhanced peroxidase-like activity for ultrasensitive detection of zearalenone in cereals.

Abstract

A novel peroxidase-like nanozyme has beenconstructed by decorating two-dimensional Ti3C2Tx nanosheets (Ti3C2Tx NSs) with gold nanoparticles (AuNPs) to develop a colorimetric and photothermal dual-mode immunosensor. TheTi3C2Tx/AuNPs nanocomposite-catalyzed 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 reaction system produces the one-electron oxidation product of TMB (oxTMB), which exhibits color change and strong near-infrared (NIR) laser-driven photothermal effect at 808nm laser irradiation. Given these characteristics, the developed immunosensor achieves ultrasensitive dual-mode detection of zearalenone (ZEN) by measuring colorimetric and photothermal signals with a microplate reader and a portable infrared thermometer, respectively. Under optimal working conditions, the limit of detection (LOD) of ZEN is 0.15 pg mL-1 for thecolorimetric mode and 0.48 pg mL-1 for thephotothermal mode. Inthe analysis of actual contaminated cereals samples, the test result of this method wasconsistent with that of UPLC-MS/MS. The proposed colorimetric and photothermal dual-mode immunosensor offers a new strategy for the low-cost detection of hazardous substances. Theapplication of awidely used household infrared thermometer makes the signal readout more convenient, which provides great prospects in food safety and environment inspection applications.