Semiconductor quantum dots (QDs) are highly fluorescent nanocrystals that have abundant potential for uses in biological imaging and sensing. However, the best materials are synthesized in hydrophobic surfactants that prevent direct aqueous solubilization. While several methods have been developed to impart water-solubility, an aqueous QD dispersion has no inherent useful purpose and must be functionalized further. Due to the colloidal nature of QD dispersions, traditional methods of chemical conjugation in water either have low yields or cause irreversible precipitation of the sample. Here, we describe several methods to water-solubilize QDs and further functionalize the materials with chemical and/or biological vectors.
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This work was supported by the ACS PRF (50859-ND10) and by funds from the University of Illinois at Chicago. We would like to thank Prof. Hedi Mattoussi for helpful discussions concerning the synthesis of cap-exchanged CdSe/CdZnS QDs.
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