Ultrasensitive and Rapid Detection of Pesticide Residues in Vegetables by Aptamer-Functionalized Carbon Nanotube Field-Effect Transistor Biosensors

Food safety issues caused by pesticide residues have received increasing attention from countries worldwide, and regions such as the European Union (EU) have set more stringent standards for pesticide residues. In recent years, aptamer-functionalized field-effect transistor (FET) aptasensors have demonstrated tremendous potential in pesticide residue detection due to their ultrahigh sensitivity and real-time response. In this study, gold nanoparticles (AuNPs) were modified on the surface of semiconducting single-walled carbon nanotubes (s-SWCNTs) via an <i>in situ</i> synthesis method. Through this method, an aptamer-functionalized s-SWCNT FET aptasensor was constructed to detect pesticide residues. Aptamer probes modified on the surface could specifically recognize various organophosphorus pesticides (OPs) and generate electrical signals, thereby achieving high sensitivity and selectivity for their detection. The limits of detection for three representative OPs were 0.51 fM (chlorpyrifos), 0.47 fM (isocarbophos), and 0.21 fM (omethoate). This biosensor demonstrates several advantages, and it shows great potential for the trace-level detection of pesticide residues.