Research On Electrochemical Immunosensing Based On Cobalt Boron Nanoarrays To Detect Tumor Markers

Cancer has become one of the important diseases that seriously affect human health and threaten human life.Early detection and diagnosis are effective ways to treat cancer.And detection of tumor markers is the most effective way to monitor cancer early.Electrochemical immunoassay has the advantages of high sensitivity,low detection limit,and fast and convenient.Therefore,it is significance to accurately detect tumor markers.Transition metal-based borides and their borates have become an important class of materials in scientific and technological research due to their unique electrical conductivity,pyroelectricity,and superhardness.Based on cobalt boride nanowires,cobalt boride nanosheets,and cobalt borate nanosheet arrays,a series of electrochemical immunosensor and photoelectrochemical immunosensor are successfully prepared in this dissertation.This not only improves the sensitivity and linear detection range of the self-made immunosensor,but also provides a new strategy for detecting tumor markers.The main research contents are as follows:1.Gold and Nile Blue A（NBA）modified cobalt boride（Co-B）nanowire arrays were synthesized for the first time,and used as three-dimensional nanoarray electrodes to detect prostate specific antigens（PSA）.The precursor Co O nanowires were prepared by hydrothermal method,Co-B nanoarrays were prepared by in-situ reduction in 10%Na BH₄,and Au nanoparticles were electrodeposited on the surface of Co-B nanoarrays.NBA/Au/Co-B nanocomposites were used as immune probes to construct a sensitive and free-labeled immunosensor for the detection of PSA.A series of physical characterization methods were used to characterize the structure of NBA/Au/Co-B nanocomposites,and electrochemical characterizations of the immunosensor were also conducted.The immunosensor has lower detection limit of 2.77 pg·m L^-1（S/N=3）,higher sensitivity of 484μA·cm^-2·(ng·m L^-1)^-1,and wider linear range of 10 pg·m L^-1～50 ng·m L^-1.In addition,the results were also compared with obtained by Enzyme-linked immunosorbent assay（ELISA）,showing a satisfactory result,and it is expected to be used to detect tumor markers in the clinic.2.Gold and Thionone（Thi）modified cobalt boride nanosheet arrays were synthesized for the first time,and used as a three-dimensional nanoarray electrode for the detection of human chorionic gonadotropin（HCG）.The three-dimensional Co-B nanoarrays with different morphologies were prepared by electrodeposition.The Au nanoparticles were electrodeposited on the surface of the Co-B nanosheets.The Thi/Au/Co-B nanocomposites were used as an immune probe to construct a sensitive free-labeled immunosensor for detecting HCG.The Thi/Au/Co-B nanocomposites were physically characterized by a series of means.And the electrochemical properties of the HCG immunosensor were studied under optimal experimental conditions.The immunosensor has lower detection limit of 2.8 pg·m L^-1（S/N=3）and wider linear range of 10 pg·m L^-1～50 ng·m L^-1,with excellent stability,reproducibility and specificity.Compared with the results of ELISA,the results are satisfactory and have broad application prospects.3.Cobalt-borate（Co-Bi）nanosheet array was used as the electrode material,and Au@Mn₂O₃ was used as a labeled probe to prepare a dual-antibody sandwich photoelectrochemical immunosensor for detecting carcinoembryonic antigen（CEA）.Co-Bi nanosheets were prepared by electrodeposition,and the larger specific surface area was used to capture the primary antibody Ab₁-CEA.The synthesized Au@Mn₂O₃ was used to label the secondary antibody Ab₂-CEA,thereby constructing a"sandwich"Sandwich type photoelectrochemical immunosensor for CEA detection.The synthesized nanomaterials were physically characterized by a series of characterization methods.Under the optimal experimental conditions,the immunosensor has a lower detection limit of 5.0 pg·m L^-1（S/N=3）,a wider linear range of 0.1 ng·m L^-1～1000 ng·m L^-1.The photoelectrochemical immunosensor can be used to detect CEA in actual serum because of its excellent specificity,stability and reproducibility.