B, N co-doped graphene synergistic catalyzed ZnO quantum dots with amplified cathodic electrochemiluminescence for fabricating microcystin-LR aptasensor

Abstract

Exploring efficient methods for microcystin-LR (MC-LR) detection is of great significance for protecting ecological environment safety and human health. Herein, an MC-LR aptasensor was fabricated based on the synergistic amplified cathodic electrochemiluminescence (ECL) of the functional nanocomposite of ZnO quantum dots decorated B, N co-doped graphene (BNG/ZnO). With K2S2O8 as co-reactant, a robust cathodic ECL emission of BNG/ZnO was observed based on the synergistic catalytic effect of B, N in graphene. Interestingly, the ECL intensity of BNG/ZnO nanocomposite was 1.8, 2.9, and 5.4 times enhanced than N-doped graphene/ZnO, B-doped graphene/ZnO, and graphene/ZnO, which was because of the difference in the electronegativity of B, C, and N could generate a unique synergistic effect to make graphene-based materials realizing signal amplification. Subsequently, a novel cathodic ECL aptasensor was constructed for sensitive and selective detection of MC-LR with aptamer as the recognition element and BNG/ZnO as the luminous reagent. Under optimized conditions, the linear range of the prepared cathodic ECL aptasensor for MC-LR detection was 0.1–5000 pM, the detection limit was 0.03 pM (S/N = 3). At the same time, the proposed aptasensor had good selectivity and stability and showed satisfactory results in actual water sample analysis.