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目的利用巯基乙酸修饰的水溶性量子点(QDs)优良的光学特性实现对肝癌细胞株HCCLM6 AFP抗原的特异性免疫荧光成像。方法用巯基乙酸修饰的QDs,制备水溶性QDs-IgG复合物探针。荧光、紫外光光谱分析、琼脂糖凝胶电泳及透射电镜研究其特性。通过间接免疫荧光法,用水溶性QDs-IgG复合物探针特异性识别肝癌细胞株HCCLM6 AFP抗原。将体外培养的肝癌细胞株HCCLM6皮下接种BALB／C-nu／nu裸小鼠。手术取瘤,石蜡切片,水溶性QDs-IgG复合物探针免疫荧光成像。双光子共聚焦激光扫描荧光显微镜观察成像,并与FITC荧光进行连续激发实验比较光稳定性。结果该水溶性QDs-IgG复合物探针具有激发光谱宽、荧光强度高的特点,能与特异性抗原良好结合。用该探针对肝癌细胞及组织成像清晰,其荧光在共聚焦激光连续激发1 h情况下无明显衰减,而FITC荧光在1 h内基本猝灭。结论QDs比传统的有机荧光染料具有更优良的光学特性,适用于生物医学成像领域。
OBJECTIVE: To achieve specific immunofluorescence imaging of HCCLM6 AFP antigen by using the excellent optical properties of thioglycolic acid-modified water-soluble quantum dots (QDs). Methods QDs modified with thioglycolic acid were used to prepare water-soluble QDs-IgG complex probes. Fluorescence, UV spectroscopy, agarose gel electrophoresis and transmission electron microscopy. HCCLM6 AFP antigen was specifically identified by indirect immunofluorescence with a water-soluble QDs-IgG complex probe. In vitro cultured hepatoma cell line HCCLM6 was inoculated subcutaneously in BALB / C-nu / nu nude mice. Surgery to take tumor, paraffin sections, water-soluble QDs-IgG complex probe immunofluorescence imaging. Two-photon confocal laser scanning fluorescence microscopy imaging and FITC fluorescence and continuous excitation experiments comparing the light stability. Results The water-soluble QDs-IgG complex probe has the characteristics of broad excitation spectrum and high fluorescence intensity, and can bind well with specific antigens. With this probe, the hepatocarcinoma cells and tissues were clearly imaged. The fluorescence of the hepatoma cells and tissues did not significantly attenuate after 1 h of confocal laser excitation, while the fluorescence of FITC was quenched within 1 h. Conclusion QDs have better optical properties than traditional organic fluorescent dyes and are suitable for biomedical imaging.