28 April 2005 Dark fraction and blinking of water-soluble quantum dots in solution
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Water-soluble quantum dots (qdots) have been introduced as bright fluorophores into life sciences research. Although various photophysical pathologies of qdots have been found, how their biological applications will be affected --- particularly in the native biological environment --- has not been evaluated. By fluorescence coincidence analysis and fluorescence cross-correlation spectroscopy, we studied the dark fraction of free-diffusing qdots in aqueous solution. We were able to detect individual qdots and found significant heterogeneity --- well-distinguished dark qdots and bright qdots. We estimated the bright fraction of Qdot525-Streptavidin to be about 55%. Blinking events were also noticed in fluorescence coincidence analysis, with “on/off” timescale from submilliseconds to tens of milliseconds.
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Jie Yao, Jie Yao, Daniel R. Larson, Daniel R. Larson, Warren R. Zipfel, Warren R. Zipfel, Watt W. Webb, Watt W. Webb, "Dark fraction and blinking of water-soluble quantum dots in solution", Proc. SPIE 5705, Nanobiophotonics and Biomedical Applications II, (28 April 2005); doi: 10.1117/12.606131; https://doi.org/10.1117/12.606131

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