Clarke Samuel J, Hollmann C Annette, Zhang Zhijun, Suffern Diana, Bradforth Stephen E, Dimitrijevic Nada M, Minarik William G, Nadeau Jay L
Department of Biomedical Engineering, McGill University, Montréal, Québec H3A 2B4, Canada.
Nat Mater. 2006 May;5(5):409-17. doi: 10.1038/nmat1631. Epub 2006 Apr 16.
Semiconductor quantum dots (QDs) have been widely used for fluorescent labelling. However, their ability to transfer electrons and holes to biomolecules leads to spectral changes and effects on living systems that have yet to be exploited. Here we report the first cell-based biosensor based on electron transfer between a small molecule (the neurotransmitter dopamine) and CdSe/ZnS QDs. QD-dopamine conjugates label living cells in a redox-sensitive pattern: under reducing conditions, fluorescence is only seen in the cell periphery and lysosomes. As the cell becomes more oxidizing, QD labelling appears in the perinuclear region, including in or on mitochondria. With the most-oxidizing cellular conditions, QD labelling throughout the cell is seen. Phototoxicity results from the creation of singlet oxygen, and can be reduced with antioxidants. This work suggests methods for the creation of phototoxic drugs and for redox-specific fluorescent labelling that are generalizable to any QD conjugated to an electron donor.
半导体量子点（QDs）已被广泛用于荧光标记。然而，它们将电子和空穴转移到生物分子的能力会导致光谱变化以及对尚未被开发利用的生命系统产生影响。在此，我们报告了首个基于小分子（神经递质多巴胺）与CdSe/ZnS量子点之间电子转移的细胞生物传感器。量子点 - 多巴胺共轭物以氧化还原敏感模式标记活细胞：在还原条件下，仅在细胞周边和溶酶体中观察到荧光。随着细胞氧化性增强，量子点标记出现在核周区域，包括线粒体内部或表面。在细胞氧化性最强的条件下，整个细胞都能观察到量子点标记。光毒性由单线态氧的产生引起，并且可以通过抗氧化剂降低。这项工作提出了创建光毒性药物和氧化还原特异性荧光标记的方法，这些方法可推广到与电子供体共轭的任何量子点。
