| As a new type of fluorescent labels, quantum dots (QDs) offer a number of attractive features that superior to classical fluorescent labels, including broad excitation spectra, relatively broad and small luminescence bands, large Stokes shift, which make them have broad potential applications in biomedical research, such as Cellular Staining, biological fluorescent labeling and immunodetection.To make good effect of QDs in biomedical detection, there are two difficult points:how to improve the biocompatibility and quantum yield of QDs, and how to conjugate QDs with biological molecules and get stable bioprobes.The main work of this thesis is to synthesize high-quality water-soluble CdTe QDs with an improved hydrothermal method, conjugate QDs with antibodies to make stable probes, and make use of these probes in the detection of human chorionic gonadotropin (HCG). The main contents and results are summarized as follows:(1) With water-soluble agent Na2TeO3 rather than Te powder as the Te precursor, reduced the hydrothermal method from two steps to one step.(2) Synthesized QDs in one-step hydrothermal method by using both glutathione (GSH) and trisodium citrate (C6H5Na3O7·H2O) as modifier and stabilizer. The fluorescence emission range of the product is 540nm-620nm, the QY can up be to 68.4%, and the diameter measured by TEM is about 10nm.(3) Compared the influence to the quantum dots fluorescence intensity of using agents EDC, NHS and glutarie as the crosslinking agent, and found that NHS is the most suitable agent for the conjugation of QDs and antibodies.(4) Conjugated QDs and HCG antibody with NHS, and confirmed that the probes are stable by dot immuno assay.(5) The as-prepared probes were used in the detection of HCG antigen, with the detection limit of 100ng. |
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