Potential-Resolved Electrochemiluminescence for Determination of Two Antigens at the Cell Surface

The potential-resolved electrochemiluminescence (ECL) was achieved for the determination of two antigens at the cell surface through a potential scanning on the electrode. Luminol and Ru­(bpy)3 2+ groups as ECL probes were linked with the antibodies to recognize the corresponding antigens on the cell surface. A self-quenching of luminescence from the luminol group under negative potential was initialized by the introduction of concentrated aqueous luminol, which offered accurate measurements of the luminescence from luminol and Ru­(bpy)3 2+ groups under positive and negative potentials, respectively. Using this strategy, carcinoembryonic (CEA) and alphafetoprotein (AFP) antigens on cells as the models were quantified serially through a potential scanning. Different patterns of luminescence were observed at MCF 7 and PC 3 cells, which exhibited that the assay can characterize the cells with a difference expression of antigens. Compared with fluorescence measurement, the potential resolved ECL for the detection of two analytes was not limited by the spectrum difference of probes. The strategy involving potential-induced signals required a simplified optical setup and eventually offered an alternative imaging method for multiply antigens in immunohistochemistry.