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Ultrasmall visible-to-near-infrared emitting silver-sulfide quantum dots for cancer detection and imaging
Author(s): Rui Tang; Baogang Xu; Duanwen Shen; Gail Sudlow; Samuel Achilefu
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Paper Abstract

The large size of many near infrared (NIR) fluorescent nanoparticles prevents rapid extravasation from blood vessels and subsequent diffusion to tumors. This confines in vivo uptake to the peritumoral space and results in high liver retention. We developed a viscosity modulated approach to synthesize ultrasmall silver sulfide quantum dots (QDs) with distinct tunable light emission from visible to near-infrared in spectrum and a QD core diameter between less than 5 nm. Further functionalization of these Ag2S QDs with different type of molecules such as targeting peptides, retains monodisperse, relatively small water soluble QDs without loss of the functionality of the peptide’s high binding affinity to cancerous tumor. Fluorescence and electron microscopy showed that selective integrin-mediated internalization was observed only in cancer cells treated with the peptide-labeled QDs, demonstrating that the unlabeled hydrophilic nanoparticles exhibit characteristics of negatively charged fluorescent dye molecules, which typically do not internalize in cells. The biodistribution profiles of intravenously administered QDs in different mouse models of cancer reveal an exceptionally high tumor-to-liver uptake ratio, suggesting that the small sized QDs evaded conventional opsonization and subsequent high uptake in the liver and spleen. The seamless tunability of the QDs over a wide spectral range with only a small increase in size, as well as the ease of labeling the bright and non-cytotoxic QDs with biomolecules, provides a platform for multiplexing information, tracking the trafficking of single molecules in cells, and selectively targeting disease biomarkers in living organisms without premature QD opsonization in circulating blood.

Paper Details

Date Published: 20 February 2018
PDF: 11 pages
Proc. SPIE 10508, Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X, 105080G (20 February 2018); doi: 10.1117/12.2300944
Show Author Affiliations
Rui Tang, Washington Univ. School of Medicine in St. Louis (United States)
Baogang Xu, Washington Univ. in St. Louis (United States)
Duanwen Shen, Washington Univ. School of Medicine in St. Louis (United States)
Gail Sudlow, Washington Univ. School of Medicine in St. Louis (United States)
Samuel Achilefu, Washington Univ. School of Medicine in St. Louis (United States)
Washington Univ. in St. Louis (United States)


Published in SPIE Proceedings Vol. 10508:
Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X
Samuel Achilefu; Ramesh Raghavachari, Editor(s)

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