Cost-effective, label-free electrochemical aptasensors for rapid detection of concanavalin A with screen printed electrodes

Intake of Concanavalin A (Con A), a hazardous lectin protein commonly discovered in legume vegetables, could cause various systemic symptoms including rash, nausea, vomiting, diarrhea, etc. Herein, we present a novel label-free and cost-effective electrochemical Con A aptasensor. [Fe(CN) 6 ] 3−/4- ions in testing buffer not only generate redox peaks during electrochemical scan, but also serve as electron acceptor/donor to enhance electron transfer. Anti-Con A aptamer is immobilized on surface of screen printed electrode to capture Con A molecules and form aptamer-protein complex, which hinders electron transfer near electrode surface and causes a decrease in peak current value. The constructed aptasensor displays a low detection limit of 17.88 ng/mL (around 171.92 pM), as well as good specificity against other legume lectins. The practicality of electrochemical sensors was evaluated using real-world samples, demonstrating their ability to rapid detect Con A in crude protein extracts from jack bean seeds. This work provides novel tools for rapid evaluation of Con A content in massive samples, which is required in food safety inspection and safety breeding of legume vegetables.