Article

Quantum dots: The new development of FRET

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Abstract

Fluorescence resonance energy transfer (FRET) has broad applications in the study of the interactions of biological macromolecules, immunoassay, nucleic acid detection and so on. However many organic dyes conventionally used in FRET have functional limitations such as low resistance to photobleaching, narrow excitation bands coupled with broad emission bands, all of which have limited the development and the application of FRET. Therefore new pairs of energy donor and acceptor are needed. Because of the advantages over organic dyes, quantum dots (QDs) have expanded the range of FRET and have been considered as new and significant development trend of FRET nowadays. The theory of FRET and the applications of QDs in FRET are reviewed in this article.

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... 荧光共振能量转移(Föster resonance energy transfer, FRET)是一种发生在供体和受体之间的光物理进程, 当 供体的荧光发射光谱与受体的吸收光谱很好重叠, 并且 二者之间的距离在 1~10 nm 范围时, 供体荧光大幅度 降低, 受体荧光显著增强 [24] . 根据这种原理, 可以对受 体荧光信号进行放大, 从而提高检测的灵敏度. ...
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A novel functionally PEGylated quantum dot (QD) was prepared by a coprecipitation method in the presence of the biotin-PEG/polyamine block copolymer. When CdCl2 and Na2S were mixed in aqueous media in the presence of the biotin-PEG-b-poly(2-(N,N-dimethylamino)ethyl methacrylate) [biotin-PEG/PAMA], a CdS QD with a size of ca. 5 nm was prepared. The polyamine segment was anchored on the surface of the formed CdS nanoparticle, whereas the PEG segment was tethered on the surface to form a hydrophilic palisade, thus improving the dispersion stability in aqueous media even under a high salt concentration condition. An effective fluorescent resonance energy transfer (FRET) was observed by the specific interaction of the biotin-PEG/PAMA stabilized CdS QD with TexasRed-labeled streptavidin of the physiological ionic strength of 0.15 M. The extent of the energy transfer was in proportion to the concentration of the TexasRed-streptavidin. This FRET system using the PEGylated CdS QD coupled with fluorescent-labeled protein can be utilized as a highly sensitive bioanalytical system.
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Fluorescent semiconductor nanocrystals, known as quantum dots (QDs), have several unique optical and chemical features. These features make them desirable fluorescent tags for cell and developmental biological applications that require long-term, multi-target and highly sensitive imaging. The improved synthesis of water-stable QDs, the development of approaches to label cells efficiently with QDs, and improvements in conjugating QDs to specific biomolecules have triggered the recent explosion in their use in biological imaging. Although there have been many successes in using QDs for biological applications, limitations remain that must be overcome before these powerful tools can be used routinely by biologists.