Magnetic Mesoporous Organic-Inorganic NiCo2O4 Hybrid Nanomaterials for Electrochemical Immunosensors

This study demonstrates a facile and feasible strategy toward the development of advanced electrochemical immunosensors based on chemically functionalized magnetic mesoporous organic inorganic hybrid nanomaterials, and the preparation, characterization, and measurement of relevant properties of the immunosensor for detection of carcinoembryonic antigen (CEA, as a model analyte) in clinical immunoassays. The as-prepared nanomaterials composed of a magnetic mesoporous NiCo2O4 nanosheet, an interlayer of Nafion/thionine organic molecules and a nanogold layer show good adsorption properties for the attachment of horseradish peroxidase-labeled secondary anti-CEA antibody (HRP-anti-CEA). With a sandwich-type immunoassay format, the functional bionanomaterials present good analytical properties to facilitate and modulate the way it was integrated onto the electrochemical immunosensors, and allows the detection of CEA at a concentration as low as 0.5 pg/mL. Significantly, the immunosensor could be easily regenerated by only using an external magnet without the need of any dissociated reagents. Importantly, the as-synthesized magnetic mesoporous NiCo2O4 nanomaterials could be further extended for detection of other biomarkers or biocompounds.