Le Gac Séverine, Vermes Istvan, van den Berg Albert
BIOS the Lab-on-a-Chip group, MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
Nano Lett. 2006 Sep;6(9):1863-9. doi: 10.1021/nl060694v.
Quantum dots (Qdots) are nanoparticles exhibiting fluorescent properties that can be used for cell staining. We present here the development of quantum dots conjugated to Annexin V for specific targeting of apoptotic cells, for both apoptosis detection and staining of apoptotic "living" cells. For that purpose, Qdots Streptavidin Conjugates are coupled to biotinylated Annexin V, a 35-kDa protein which specifically recognizes and binds to phosphatidylserine (PS) moieties present on the outer membrane of apoptotic cells and not on healthy or necrotic cells. By using Annexin V, our Qdots probes are made specific for apoptotic cells. Staining of apoptotic cells was checked using fluorescence and confocal microscopy techniques and nonfixed cells. It is shown here that Qdots are insensitive to bleaching after prolonged exposure as opposed to organic dyes. This makes Qdots excellent candidates to continuously follow fast changes occurring at the membrane of apoptotic cells and facilitates time-lapse imaging as they alleviate any bleaching issue.
量子点（Qdots）是具有荧光特性的纳米颗粒，可用于细胞染色。我们在此展示了与膜联蛋白V共轭的量子点的开发，用于凋亡细胞的特异性靶向，既用于凋亡检测，也用于凋亡“活”细胞的染色。为此，量子点链霉亲和素共轭物与生物素化的膜联蛋白V偶联，膜联蛋白V是一种35 kDa的蛋白质，它能特异性识别并结合凋亡细胞外膜上存在的磷脂酰丝氨酸（PS）部分，而健康细胞或坏死细胞上则不存在。通过使用膜联蛋白V，我们的量子点探针可对凋亡细胞具有特异性。使用荧光和共聚焦显微镜技术以及非固定细胞检查凋亡细胞的染色情况。结果表明，与有机染料不同，量子点在长时间曝光后对光漂白不敏感。这使得量子点成为持续跟踪凋亡细胞膜上快速变化的极佳候选者，并有助于进行延时成像，因为它们缓解了任何光漂白问题。
