Application of indium tin oxide device in gold-coated magnetic iron solid support enhanced electrochemiluminescent immunosensor for determination of carcinoma embryonic antigen

In this paper, a sandwich-type electrochemiluminescent (ECL) immunosensor was fabricated for the detection of carcinoma embryonic antigen (CEA) on a portable indium tin oxide (ITO) device. Gold-coated magnetic iron nanoparticles (Fe@Au MNPs) were synthesized as solid support to immobilize CEA-primary monoclonal antibody (CEA-McAb1). CdTe quantum dots (QDs) was used to label CEA-secondary antibodies (CEA-McAb2). The transparent ITO device was fabricated using a simple, low-cost, fast acid etch technique, which integrated counter electrode, reference electrode and working electrode in a piece of ITO glass. Under cyclic voltammetry condition, the ECL of CdTe QDs was enhanced by the energy transfer reaction from the excited Fe@Au MNPs surface plasmon resonance to CdTe QDs, and the possible mechanism was investigated. The proposed immunosensor provided a wide linear response range (0.001–50 ng mL−1) with a low detection limit (0.38 pg mL−1). The assay results of CEA in clinical serum samples were in a good agreement with the standard enzyme-linked immunosorbent assay (ELISA) tests. The proposed enhanced ECL immunosensor may provide potential application for detection of other tumor markers.