ECL (electrochemiluminescence) immunosensor for detecting tumor markers and preparation method and applications thereof

The invention discloses an ECL (electrochemiluminescence) immunosensor for detecting tumor markers and a preparation method and applications thereof. The immunosensor comprises a working electrode, a reference electrode and a counter electrode, wherein the working electrode is a gold electrode, cysteamine, glutaraldehyde, a tumor marker first-antibody, a tumor marker, and a composite functionalized nanosphere are sequentially decorated on the surface of the gold electrode, the composite functionalized nanosphere is simultaneously marked by a tumor marker second-antibody and an ECL marker, and non-specific active sites are closed by using bovine serum albumins. The preparation method comprises the steps of preparing the gold electrode on which the tumor marker first-antibody is fixedly carried; synthesizing the composite functionalized nanosphere simultaneously marked by the tumor marker second-antibody and the ECL marker; and finally, assembling the obtained gold electrode and the composite functionalized nanosphere into an ECL immunosensor. The ECL immunosensor disclosed by the invention is high in sensitivity, rapid in analysis speed, strong in stability and selectivity, good in reproducibility, easy to operate, and flexible in method.