A new immunoassay method for Carcinoembryonic Antigen based on fluorescence induced by laser and labeled with nanoparticles is presented. Core-shell SiO₂ fluorescent nanoparticles were used as labels, “sandwich” model was used. Mouse anti-carcinoembryonic antigen (CEA) monoclonal antibody was immobilized on slides, then 1～2 µL CEA was added, and the other mouse anti-CEA monoclonal antibody labeled with nanoparticles was added, after CEA and antibody recognized, the fluorescent signal was quantified with an laser-induced fluorescence millimeter array detection platform based on optical fiber. The fluorescence intensity has a linear relationship with the concentration of CEA in the range of 1～80 pg, with the absolute limit detection of CEA being 0.3 pg. The relative standard deviation (RSD) for 5 parallel measurements of CEA (40 pg) was 5.5%.

Key words: nanoparticles, laser induced fluorescence, sensor array, carcinoembryonic antigen