Magnetic Mesoporous Organic−Inorganic NiCo₂O₄ Hybrid Nanomaterials for Electrochemical Immunosensors

Abstract

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 NiCo(2)O(4) 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 NiCo(2)O(4) nanomaterials could be further extended for detection of other biomarkers or biocompounds.