A solid-state electrochemiluminescence biosensor for Con A detection based on CeO2@Ag nanoparticles modified graphene quantum dots as signal probe

A solid-state electrochemiluminescence (ECL) biosensor for the detection of concanavalin A (Con A) was constructed using graphene quantum dots (GQDs) as luminophore, which were loaded on polyamidoamine (PAMAM) functionalized CeO2@Ag NPs by the interaction between the NH2 of PAMAM and the COOH of GQDs. The electrodepositing gold layers were used as matrix to immobilize glucose oxidase (GOx). GOx served as recognition elements to further capture Con A by the specific interaction between carbohydrate and Con A. With the increase of the concentration of Con A, the amount of GOx-CeO2@Ag-GQDs incubated onto the electrode was increased and a higher ECL signal was obtained. The constructed biosensor exhibited a sensitive response towards Con A and a low detection limit of 0.16 pg/mL was obtained. Such a construction strategy provides a new approach for applying GQDs to establish a solid-state ECL biosensor.