TY - JOUR
T1 - Paramagnetic, silicon quantum dots for magnetic resonance and two-photon imaging of macrophages
AU - Tu, Chuqiao
AU - Ma, Xuchu
AU - Pantazis, Periklis
AU - Kauzlarich, Susan M.
AU - Louie, Angelique Y.
PY - 2010
Y1 - 2010
N2 - 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 (SiMn QDs) and demonstrate that they are detectable by both MRI and near-infrared excited, two-photon imaging. The SiMn 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 SiMn QDs have an r1 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 T1-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.
AB - 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 (SiMn QDs) and demonstrate that they are detectable by both MRI and near-infrared excited, two-photon imaging. The SiMn 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 SiMn QDs have an r1 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 T1-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.
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U2 - 10.1021/ja909303g
DO - 10.1021/ja909303g
M3 - Article
C2 - 20092250
AN - SCOPUS:77249113267
VL - 132
SP - 2016
EP - 2023
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 6
ER -