近场光学显微镜结合量子点标记人胃腺癌SGC-7901细胞靶点的观察

扫描近场光学显微镜突破衍射极限,具有纳米量级的空间分辨率,量子点(QD s)标记有荧光强度高且抗光漂白能力强等优点。结合上述两种技术,对人胃腺癌SGC-7901细胞膜表面特异性结合的叶酸受体(FR)进行成像探测,获得了叶酸受体在SGC-7901细胞膜表面上的分布,以及细胞内化外源性叶酸过程中叶酸受体在细胞膜表面的分布变化,成像的光学分辨率达到120 nm。实验结果表明:特异性结合的叶酸受体在SGC-7901细胞膜表面的分布,绝大部分是以聚集体的形式存在。随着SGC-7901细胞内化叶酸量的增加,叶酸受体在细胞膜表面的分布密度逐渐降低,并在经过120 m in左右趋于稳定。上述方法和手段为实现单细胞水平上靶点分布和变化的长期监测,肿瘤细胞内化受体的机制研究提供了新的技术途径。

The Detection of the Folic Acid Recepter of the Human Gastric Cancer SGC-7901 Cell by SNOM and Quantum Dots Labelling

Scanning near-field optical microscopy(SNOM) circumvents the diffraction of conventional light microscopy and is able to achieve subwavelength optical resolution.Quantum dots(QDs) are nanoparticles which have strong fluorescence intensity and more are resistant to photobleaching than the organic fluorescence probes in cell biology and biomedicine.In this report,a new fluorescence microscope approach,which combined attributes from both SNOM and QDs labelling method,was used to detect the distribution of the specific binding folic acid recepter(FR) on the membrane of the human gastric cancer SGC-7901 cell.The research result showed: the specific FR labeled with QDs were imaged at a spatial resolution of ~120 nm,a large number of FR on the membrane were assembled,and as the time of endocytosis was increased,the FR's density obviously decreased,finally unchanged by the time of 120 min.The Above results illustrated that the combination of SNOM imaging and QDs labeling opened up new possibilities for single biomolecular imaging and long-term monitoring.