Nano Research

, Volume 2, Issue 6, pp 500–508

Proton-resistant quantum dots: Stability in gastrointestinal fluids and implications for oral delivery of nanoparticle agents

Authors

  • Aaron M. Mohs
    • Departments of Biomedical Engineering and ChemistryEmory University and Georgia Institute of Technology
  • Hongwei Duan
    • Departments of Biomedical Engineering and ChemistryEmory University and Georgia Institute of Technology
  • Brad A. Kairdolf
    • Departments of Biomedical Engineering and ChemistryEmory University and Georgia Institute of Technology
  • Andrew M. Smith
    • Departments of Biomedical Engineering and ChemistryEmory University and Georgia Institute of Technology
    • Departments of Biomedical Engineering and ChemistryEmory University and Georgia Institute of Technology
Open AccessResearch Article

DOI: 10.1007/s12274-009-9046-3

Cite this article as:
Mohs, A.M., Duan, H., Kairdolf, B.A. et al. Nano Res. (2009) 2: 500. doi:10.1007/s12274-009-9046-3

Abstract

Semiconductor quantum dots (QDs) have shown great promise as fluorescent probes for molecular, cellular and in vivo imaging. However, the fluorescence of traditional polymer-encapsulated QDs is often quenched by proton-induced etching in acidic environments. This is a major problem for applications of QDs in the gastrointestinal tract because the gastric (stomach) environment is strongly acidic (pH 1–2). Here we report the use of proton-resistant surface coatings to stabilize QD fluorescence under acidic conditions. Using both hyperbranched polyethylenimine (PEI) and its polyethylene glycol derivative (PEG-grafted PEI), we show that the fluorescence of core shell CdSe /CdS/ ZnS QDs is effectively protected from quenching in simulated gastric fluids. In comparison, amphiphilic lipid or polymer coatings provide no protection under similarly acidic conditions. The proton-resistant QDs are found to cause moderate membrane damage to cultured epithelial cells, but PEGylation (PEG grafting) can be used to reduce cellular toxicity and to improve nanoparticle stability.

https://static-content.springer.com/image/art%3A10.1007%2Fs12274-009-9046-3/MediaObjects/12274_2009_9046_Fig1_HTML.jpg

Keywords

Nanoparticle quantum dot oral delivery gastrointestinal polyethylenimine (PEI) polyethylene glycol (PEG)

Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2009