Phosphorescent immunosensor for simple and sensitive detection of microcystin-LR in water

Abstract

A simple and sensitive Mn–ZnS quantum dot room-temperature phosphorescent immunosensor for detecting microcystin-LR was developed. This sensor adopted antigens and antibodies as recognition units and used Mn–ZnS RTP QDs as sensing materials to specifically bind with MC-LR. The structurally specific binding between the microcystin-LR antibody and MC-LR led to the aggregation of antibody-crosslinked QDs, and then the electrons of QDs would be transferred to the complex, leading to the phosphorescence quenching of QDs. The microcystin-LR antigen–antibody specific binding site was first analyzed. This phosphorescent immunosensor rapidly and sensitively detected microcystin-LR, with linear ranges of 0.2–1.5 μg L⁻¹ and 1.5–20 μg L⁻¹ and a detection limit of up to 0.024 μg L⁻¹. Meanwhile, coexisting pollutants of microcystin-LR in water did not significantly interfere with microcystin-LR detection. The new sensor was applied to detect real water samples and showed high sensitivity and selectivity.