Gold nanocrystals modified electrochemical aptasensor for ultra-trace level detection of malathion in environmental samples

Abstract

Abstract The abnormal concentrations of organophosphorus pesticides (OPs) in agricultural residues have raised serious concerns regarding food safety and environmental pollution. The trace level detection of these toxic OPs has therefore garnered great attention in the past few decades. Herein, gold nanocrystals modified electrochemical aptasensor has been reported for the detection of a widely used organophosphorus pesticide, malathion. By virtue of the high specificity of the aptamer towards malathion and enhanced surface area provided by the nanocrystals, the designed probe exhibits excellent selectivity and sensitivity for malathion. The conformational changes of aptamer due to its specific binding to malathion induces a large variation in the electrochemical responses of the redox moiety, methylene blue. The gold nanocrystals@aptamer probe exhibits excellent sensitivity in the linear range from 1 pm to 100 nm with 1 pM as the detection limit. Owing to its high reliability and robustness in the spiked samples, the developed nanoprobe paves the way for ultra-trace level detection of malathion in environmental samples.