Tu, Chuqiao and Ma, Xuchu and Pantazis, Periklis and Kauzlarich, Susan M. and Louie, Angelique Y. (2010) Paramagnetic, Silicon Quantum Dots for Magnetic Resonance and Two-Photon Imaging of Macrophages. Journal of the American Chemical Society, 132 (6). pp. 2016-2023. ISSN 0002-7863 http://resolver.caltech.edu/CaltechAUTHORS:20100324-111336725
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Quantum dots (QDs) are an attractive platform for building multimodality imaging probes, but the toxicity for typical cadmium QDs limits enthusiasm for their clinical use. Nontoxic, silicon QDs are more promising but tend to require short-wavelength excitations which are subject to tissue scattering and autofluorescence artifacts. Herein, we report the synthesis of paramagnetic, manganese-doped, silicon QDs (Si_(Mn) QDs) and demonstrate that they are detectable by both MRI and near-infrared excited, two-photon imaging. The Si_(Mn) QDs are coated with dextran sulfate to target them to scavenger receptors on macrophages, a biomarker of vulnerable plaques. TEM images show that isolated QDs have an average core diameter of 4.3 ± 1.0 nm and the hydrodynamic diameters of coated nanoparticles range from 8.3 to 43 nm measured by dynamic light scattering (DLS). The Si_(Mn) QDs have an r_1 relaxivity of 25.50 ± 1.44 mM^(−1) s^(−1) and an r_2 relaxivity of 89.01 ± 3.26 mM^(−1) s^(−1 )(37 °C, 1.4 T). They emit strong fluorescence at 441 nm with a quantum yield of 8.1% in water. Cell studies show that the probes specifically accumulate in macrophages by a receptor-mediated process, are nontoxic to mammalian cells, and produce distinct contrast in both T_1-weighted magnetic resonance and single- or two-photon excitation fluorescence images. These QDs have promising diagnostic potential as high macrophage density is associated with atherosclerotic plaques vulnerable to rupture.
|Additional Information:||© 2010 American Chemical Society. Received November 2, 2009. Publication Date (Web): January 21, 2010. We acknowledge the National Institute of Health (HL081108-01, EB008576-01, and EB006192), a German Science Foundation (DFG) Postdoctoral Fellowship, and the NMR award of the University of California, Davis for support of this work. We thank Dr. Xiaobo Liu for help in two-photon imaging.|
|Official Citation:||Paramagnetic, Silicon Quantum Dots for Magnetic Resonance and Two-Photon Imaging of Macrophages Chuqiao Tu, Xuchu Ma, Periklis Pantazis, Susan M. Kauzlarich, Angelique Y. Louie Journal of the American Chemical Society 2010 132 (6), 2016-2023|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||29 Mar 2010 22:46|
|Last Modified:||26 Dec 2012 11:55|
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