A graphene and multienzyme functionalized carbon nanosphere-based electrochemical immunosensor for microcystin-LR detection

A graphene-based immunosensor was fabricated for the detection of microcystin-LR using a horseradish peroxidase–carbon nanosphere–antibody system for signal amplification. Graphene and chitosan were used as immobilization materials to improve the electrochemical performance of the electrode. Signal amplification was achieved using multienzyme functionalized carbon nanosphere. This approach provided a linear range from 0.05 to 15 μg L−1 microcystin-LR with a detection limit of 0.016 μg L−1. Analytical detection of microcystin-LR in environmental water samples were demonstrated by comparing the results obtained using immunosensor and high-performance liquid chromatography. This electrochemical immunosensor showed good performance with high sensitivity, acceptable stability, repeatability and the potential for use in routine water quality monitoring for various toxins.

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► Graphene was used to improve the electrochemical performance of the immunosensor.
► Amplified immunosensing was achieved based on functionalized carbon nanospheres.
► A low detection limit and wide linear range of microcystin-LR were obtained.
► This method was applied for the analysis of microcystin-LR in real water sample.