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Journal of Biomedicine and Biotechnology
Volume 2007 (2007), Article ID 70145, 10 pages
Research Article

Fluorescence Intensity and Intermittency as Tools for Following Dopamine Bioconjugate Processing in Living Cells

1Department of Biomedical Engineering, McGill University, 3775 Rue University, 316 Lyman Duff Medical Building, Montréal, QC H3A 2B4, Canada
2Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, QC H3A 2K6, Canada
3Department of Physics, McGill University, 3600 Rue University, Montréal, QC H3A 2T8, Canada

Received 10 April 2007; Revised 11 August 2007; Accepted 24 December 2007

Academic Editor: Marek Osinski

Copyright © 2007 Rafael Khatchadourian et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


CdSe/ZnS quantum dots (QDs) conjugated to biomolecules that quench their fluorescence, particularly dopamine, have particular spectral properties that allow determination of the number of conjugates per particle, namely, photoenhancement and photobleaching. In this work, we quantify these properties on a single-particle and ensemble basis in order to evaluate their usefulness as a tool for indicating QD uptake, breakdown, and processing in living cells. This creates a general framework for the use of fluorescence quenching and intermittency to better understand nanoparticle-cell interactions.