Ultrasmall visible-to-near-infrared emitting silver-sulfide quantum dots for cancer detection and imaging

Rui Tang, Baogang Xu, Duanwen Shen, Gail Sudlow, Samuel Achilefu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

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.

Original languageEnglish
Title of host publicationReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X
EditorsSamuel Achilefu, Ramesh Raghavachari
PublisherSPIE
ISBN (Electronic)9781510615014
DOIs
StatePublished - Jan 1 2018
EventReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X 2018 - San Francisco, United States
Duration: Jan 29 2018Jan 30 2018

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume10508
ISSN (Print)1605-7422

Conference

ConferenceReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X 2018
Country/TerritoryUnited States
CitySan Francisco
Period01/29/1801/30/18

Keywords

  • Quantum dot
  • cancer
  • fluorescence
  • integrin
  • near infrared
  • optical imaging
  • silver sulfide

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