Nanomaterials have been widely used to immobilize biomolecules, amplify the signals and concentrate the analytes for detection with good properties including large surface area, good adsorption capacity and high surface activity. In recent years, nanomaterials such as carbon nanomaterials, noble metal nanomaterials, polymers, are widely applied to research and develop immunosensors with high sensitivity and selectivity, which monitor the antigen-antibody reaction for the detection of tumor markers. This review provides an introduction of immunosensors and focuses on the design of electrochemical (EC) immunosensors, electrochemical luminscence (ECL) immunosensors and photoelectrochemical (PEC) immunosensors based on nanomaterials in nearly three years.
A novel molecular imprinted polymer (MIP) electrochemical sensor was successfully fabricated for sensitive detection of carcinomaembryonic antigen (CEA). We used CEA as template, dopamine (DA) as imprinted monomers. Through controlling electropolymerization, a "PDA-CEA"complex was achieved. After elution, the specific cavities adsorbed the target molecules. In addition, polythionine (PTh) and AuNPs were applied as the electrode modifying materials to enhance electron transfer rate and improve detection signal. Using differential pulse voltammetry (DPV) detection, the peak current decreased with the increase in concentration of CEA, and the linear response range of the MIP sensor was from 0.001 ng/mL to 1000 ng/mL with the detection limit as low as 0.2589 pg/mL. The MIP sensor had a low sample consumption, good stability, and high sensitivity, and could become a new promising method for the detection of CEA. Furthermore, this MIP sensor was demonstrated in testing CEA in human serum sample with satisfactory results.
A sandwich-type electrochemical immunosensor was developed in this study for sensitive detection of carcinoembryonic antigen (CEA) based on rGO/CS/AuNPs as a sensing platform and PTh-Au composites as signal labels. Reduced graphene oxide (rGO), Chitosan (CS) and AuNPs were layer by
layer modified on glass carbon electrode (GCE), which effectively enhanced electron transfer and provided excellent large electrochemical active surface area. Polythionine-Au composites prepared by chemical reduction method greatly amplified electrochemical signal with high conductivity and
large surface area. The prepared immunosensor showed high sensitivity, good stability and selectivity for detection of CEA with a wide range of 0.3 ng/mL to 30 ng/mL (R2 = 0.9972) and a detection limit as low as 0.1471 pg/mL. Furthermore, this sandwich-type immunosensor might
be as a versatile platform for reliable early cancer diagnostics clinical.
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