Nanoporous PtRu Alloy Enhanced Nonenzymatic Immunosensor for Ultrasensitive Detection of Microcystin‐LR

A novel nonenzymatic immunosensor for sensitive detection of Microcystin‐LR (MC‐LR) is constructed using a graphene platform combined with mesoporous PtRu alloy as a label for signal amplification. Primary antibody‐Microcystin‐LR (Ab 1 ) is immobilized onto the surface of a graphene sheet (GS) through an amidation reaction between the carboxylic acid groups attached to the GS and the available amine groups of Ab 1 . Mesoporous PtRu alloy, prepared by corrosion PtRuAl alloys, is employed as a label to immobilize secondary antibody (Ab 2 ). The resulting nanoparticles, PtRu‐Ab 2 , are used as labels for the immunosensor to detect MC‐LR. Under optimal conditions, the immunosensor exhibits a wide linear response to MC‐LR that ranges from 0.01 to 28 ng·mL −1 , with a low detection limit of 9.63 pg·mL −1 MC‐LR. The proposed immunsensor shows good reproducibility, selectivity, and stability. The assayed results of polluted water with the sandwich‐type sensor are acceptable. Importantly, this methodology may provide a promising ultrasensitive assay strategy for other environmental pollutants.