Disposable electrochemical immunosensor based on peroxidase-like magnetic silica-graphene oxide composites for detection of cancer antigen 153

A disposable electrochemical immunosensor was established for the detection of cancer antigen 153 (CA 153) using peroxidase-like magnetic silica nanoparticles/graphene oxide composites as labels and graphene oxide modified screen-printed carbon electrodes. The magnetic silica nanoparticles/graphene oxide composites were prepared via conjugating azide-functionalized magnetic silica nanoparticles to acetylene-functionalized graphene oxide by click chemistry with a copper-catalyzed 1,3-dipolar cycloaddition reaction. Structure characterization was obtained by means of atomic force microscope, X-ray diffraction and transmission electron microscope. The magnetic silica nanoparticles/graphene oxide composites showed great peroxidase-like activity. The CA 153 immunosensor was fabricated with sandwich method by immobilizing a monoclonal anti-CA 153 antibody on the graphene oxide attached on a screen-printed electrode, peroxidase-like magnetic silica nanoparticles/graphene oxide composites was used as signal label. This method was simple, inexpensive, highly sensitive, and selective for CA 153 detection with a proportional to the logarithm value of the CA 153 concentration from 10−3 to 200U/mL and the detection limit of 2.8×10−4U/mL. In addition, the assay was evaluated with CA 153 spiked serum samples and commercially available Electrochemiluminescent Analyzer obtained excellent correlation.