In situ reduction triggers the highly sensitive detection of pesticide by classic gold nanoparticle and quantum dots nanocomposite

Fluorescence turn on method is always preferable for target detection under the urgent demand to develop point-of-care portable sensors in practical applications due to its higher selectivity and less false positives. However, there is only few reports of pesticide monitoring based on this strategy so far most probably ascribed to its poor hydrophilicity and reactivity. In this work, triggered by reductant tris (2-carboxyethyl) phosphine hydrochloride (TCEP), initially fluorescence-quenched gold nanoparticles (Au NPs)-decorated quantum dots (QDs)-embedded nanobead shows obvious fluorescence turn on signal response to thiram with concentration response range of 0.01-20 mu M and limit of detection (LOD) of 7 nM due to the target-induced dissociation of Au NPs from the surface of probe nanobead. Moreover, paper sensor has been successfully developed by immersing commercial drainage membrane in probe solution for visual detection of thiram with the ultrahigh LOD (50 nM) by the naked eye. More importantly, this work, for the first time, reported an in situ reduction strategy to improve the interaction between target and nanoprobe and thus bring obvious signal output for pesticide detection with high sensitivity, demonstrating the potential to expand the detection scope of nanomaterials. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study successfully achieved high-sensitivity fluorescence detection of thiram triggered by TCEP, demonstrating the potential in developing point-of-care sensors. Additionally, a paper sensor that can be visually observed by naked eye was developed, providing new possibilities for pesticide detection. By using an in situ reduction strategy, the interaction between the target and nanoprobe was improved, leading to high sensitivity detection.