| Immunofluorescence labeling technology has made great progress in recent years.Organic fluorescent marker analysis method, in particular, has developed into a kind of commonmethods for laboratory analysis. Fluorescent markers were made by connecting the fluorescent dyeand the antibody, then the cells were labelled by specific antigen-antibody binding reaction. Underthe excitation of external light, different fluorescent markers can emit visible or infraredfluorescence. Although this technology has been widely used, there are many problems to besolved such as imaging ability, fluorescence intensity, fluorescence stability, fluorescence lifetime,multicolor imaging and biological toxicity, etc. In this paper, we study a new type of fluorescentmarkers, the artificial synthesis of semiconductor nanoparticles-quantum dots(QDs). The QDs werelinked to antibody to make a new type of immune fluorescent probe. The probe could specificallyand effectively label on the tumor cells. The quantum dots immunofluorescence labeling techniquecan overcome many problems of traditional organic fluorescent markers. In addition, we alsodiscussed the toxic effects of quantum dots immune fluorescent probes to the tumor cells culturedin vitro, then had a further understanding of the biocompatibility of the probes.The main works and conclusions are as following:In the solution of water, CdTeS quantum dots was synthesized by one-step hydrothermalmethod. This method proved to be of easy operation, good repeatability, low cost andlow toxicity. In order to turn the emission wavelengths of the QDs from visible to near-infrared range, we adjusted the time of the reaction. We wrapped the quantumdots in a layer of CdS shell to improve the stability of CdTeS quantum dots and toincrease the luminous intensity of the CdTeS/CdS core-shell structure.The CdTeS quantum dots and the CK19antibodies were covalent bonding to make quantumdots-cytokeratin19antibody fluorescent probes (QDs-CK19). Through the spectrum analysis, weknew that QDs-CK19probes basically kept the original optical properties of the CdTeS quantumdots. The excitation spectrum of the QDs-CK19fluorescent probes were wide and continuous, theemission spectrum narrow and symmetry. Under the excitation of ultraviolet light (wavelength is365nm), the probes emitted yellow fluorescence. At the same time, the originally biologicalimmune activity of the CK19antibody was not affected, the properties of the compound probeswas stable.The QDs-CK19fluorescent probes were used to mark the breast cancer cell line MDA-MB-231byone-step immunofluorescence. They could specifically and effectively recognize the antigen. Underthe ultraviolet excitation, fluorescence microscope and laser confocal microscope showed that theprobes could specifically and effectively label on the breast cancer cell line MDA-MB-231. Thefluorescence was mainly in the cytoplasm and the cytomembrane, the lifetime of the clear andbright fluorescence was long. After repeatedly high intensity of laser irradiation, the fluorescenceof quantum dots was not weakened obviously. The lifetime of the fluorescence could last more than14days.The breast cancer cells MDA-MB-231were divided into control group and QDs-CK19probes-treated group of different concentrations. After treated with the QDs-CK19probes, the cellproliferation was measured by MTT assay and the apoptosis was measured by AnnexinV-fluorescein isothiocyanate (FITC)/PI flow cytometry(FCM). Results show that in the range ofeight times the effective marking concentration, the probe would not induce apoptosis. The cell proliferation would be inhibited, when the concentration of the probes and the action timeincreased. However, the proliferation of breast cancer cells cultured in vitro would not be inhibited,when the concentration of the probes was lower than eight times the effective markingconcentration. The range of the concentration was relatively safe. |
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