Shah Bhranti S, Mao Jeremy J
Tissue Engineering and Regenerative Medicine Laboratory, Department of Biomedical Engineering, College of Dental Medicine, Columbia University Medical Center, New York, NY 10032, USA.
Methods Mol Biol. 2011;680:61-75. doi: 10.1007/978-1-60761-901-7_4.
Quantum dots (QDs) are semiconductor nanocrystals, and recently they have been shown as effective probes for cell labeling. Due to their unique spectral, physical, and chemical properties, QDs can concurrently tag multiple intercellular and intracellular components of live cells for time ranging from seconds to months. Different color QDs can label different cell components that can be visualized with fluorescent microscopy or in vivo. Here, we provide a detailed protocol for labeling postnatal and differentiated stem/progenitor cells with bioconjugated quantum dots. For example, peptide CGGGRGD is immobilized on CdSe-ZnS QDs with free carboxyl groups. These bioconjugates label selected integrins on cell membrane of human mesenchymal stem cells (hMSCs). QD concentration and incubation time to effectively label hMSCs is optimized. We discovered that bioconjugated QDs effectively label hMSCs not only during population doubling, but also during multi-lineage differentiation into osteoblasts, chondrocytes, and adipocytes. Undifferentiated and differentiated stem cells labeled with bioconjugated QDs can be readily imaged by fluorescent microscopy. Thus, quantum dots represent an effective cell labeling probe and an alternative to organic dyes and fluorescent proteins for cell labeling and cell tracking.
量子点（QDs）是半导体纳米晶体，最近它们已被证明是用于细胞标记的有效探针。由于其独特的光谱、物理和化学性质，量子点可以在从几秒到几个月的时间内同时标记活细胞的多个细胞间和细胞内成分。不同颜色的量子点可以标记不同的细胞成分，这些成分可以通过荧光显微镜或在体内可视化。在这里，我们提供了一个用生物共轭量子点标记出生后和分化的干/祖细胞的详细方案。例如，肽CGGGRGD固定在带有游离羧基的CdSe-ZnS量子点上。这些生物共轭物标记人间充质干细胞（hMSCs）细胞膜上的选定整合素。优化了有效标记hMSCs的量子点浓度和孵育时间。我们发现，生物共轭量子点不仅在群体倍增期间，而且在向成骨细胞、软骨细胞和脂肪细胞的多谱系分化过程中都能有效地标记hMSCs。用生物共轭量子点标记的未分化和分化干细胞可以很容易地通过荧光显微镜成像。因此，量子点代表了一种有效的细胞标记探针，是用于细胞标记和细胞追踪的有机染料和荧光蛋白的替代品。
