A molybdenum disulfide/gold nanorod composite-based electrochemical immunosensor for sensitive and quantitative detection of microcystin-LR in environmental samples

Abstract A sensitive electrochemical immunosensor based on a molybdenum disulfide (MoS 2 ) and gold nanorods (AuNRs) composite was developed for the detection of microcystin-LR (MC-LR). The immunosensor was constructed by immobilizing MC-LR antibody on the MoS 2 /AuNRs nanocomposite modified gold electrode. Using a competitive immunoassay format, the coated MC-LR antibody competed for MC-LR antigen with added target MC-LR, forming an antibody-antigen immunocomplex. Subsequently, horseradish peroxidase-labeled anti-MC-LR antibody (HRP-Ab 2 ) was captured and detected. Under optimal conditions, the immunosensor exhibited a linear response to MC-LR ranging from 0.01 to 20 μg L −1 with a detection limit of 5 ng L −1 at a signal to noise of 3. This electrochemical immunosensor showed good performance with high sensitivity, good stability, accepted reusability and promising applications in routine water quality monitoring for various toxins.