Web Release Date: February 1,
pH-Sensitive Photoluminescence of CdSe/ZnSe/ZnS Quantum Dots in Human Ovarian Cancer Cells
and
Mork Family Department of Chemical Engineering and Materials Science, Department of Electrical Engineering-Electrophysics, MOSIS, Information Sciences Institute, and Department of Biological Sciences, University of Southern California, Los Angeles, California 90089
Received: August 24, 2006
In Final Form: December 26, 2006
Abstract:
The photoluminescence of mercaptoacetic acid (MAA)-capped CdSe/ZnSe/ZnS semiconductor nanocrystal quantum dots (QDs) in SKOV-3 human ovarian cancer cells is pH-dependent, suggesting applications in which QDs serve as intracellular pH sensors. In both fixed and living cells the fluorescence intensity of intracellular MAA-capped QDs (MAA QDs) increases monotonically with increasing pH. The electrophoretic mobility of MAA QDs also increases with pH, indicating an association between surface charging and fluorescence emission. MAA dissociates from the ZnS outer shell at low pH, resulting in aggregation and loss of solubility, and this may also contribute to the MAA QD fluorescence changes observed in the intracellular environment.
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