磁性纳米探针流动注射化学发光检测肿瘤细胞

novel magnetic bio-bar-code nanoprobe (TE02/CoNPs/Au@Fe3O4) was fabricated by attaching aptamer TE02 and Co nanoparticle (CoNP)-labeled DNA on core-shell conjugates Au@Fe3O4 with a ratio of 1:10. The fabricated TE02/CoNPs/Au@Fe3O4 composites were immobilized on 96-well plate by hybridizing aptamer to capture probe. Upon introduction of target Ramos cells, the TE02/CoNPs/Au@Fe3O4 composites were attached on the surface of Ramos cells through specific cell-SELEX aptamer-target cell interaction. After magnetic separation and addition of linker DNA, the TE02/CoNPs/Au@Fe3O4 composites were released from cell surface through strand displacement reaction (SDR), which further acted as amplification station followed by dissolving with HNO3. As a result, a large amount of Co2+ was released. Based on Co2+-catalyzed luminol-H2O2 flow-injection chemiluminescence (FI-CL), this assay achieved highly sensitive and selective detection of Ramos cells with a linear range from 100 to 10000 cells and limit of detection (LOD) of 86 cells. In addition, the proposed method has been successfully applied to Ramos cell analysis in serum samples.