Translocation of PEGylated quantum dots across rat alveolar epithelial cell monolayers

Farnoosh Fazlollahi1 Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, USA;8 Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA

Arnold Sipos1 Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, USA;2 Department of Medicine, University of Southern California, Los Angeles, CA, USA

Yong Ho Kim1 Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, USA;2 Department of Medicine, University of Southern California, Los Angeles, CA, USA

Sarah F Hamm-Alvarez6 Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA

Zea Borok1 Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, USA;2 Department of Medicine, University of Southern California, Los Angeles, CA, USA;3 Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, CA, USA

Kwang-Jin Kim1 Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, USA;2 Department of Medicine, University of Southern California, Los Angeles, CA, USA;5 Department of Physiology and Biophysics, University of Southern California, Los Angeles, CA, USA;6 Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA;7 Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA

Edward D Crandall1 Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, USA;2 Department of Medicine, University of Southern California, Los Angeles, CA, USA;4 Department of Pathology, University of Southern California, Los Angeles, CA, USA;8 Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USACorrespondence[email protected]

show all

Abstract

Background

In this study, primary rat alveolar epithelial cell monolayers (RAECM) were used to investigate transalveolar epithelial quantum dot trafficking rates and underlying transport mechanisms.

Methods

Trafficking rates of quantum dots (PEGylated CdSe/ZnS, core size 5.3 nm, hydrodynamic size 25 nm) in the apical-to-basolateral direction across RAECM were determined. Changes in bioelectric properties (ie, transmonolayer resistance and equivalent active ion transport rate) of RAECM in the presence or absence of quantum dots were measured. Involvement of endocytic pathways in quantum dot trafficking across RAECM was assessed using specific inhibitors (eg, methyl-β-cyclodextrin, chlorpromazine, and dynasore for caveolin-, clathrin-, and dynamin-mediated endocytosis, respectively). The effects of lowering tight junctional resistance on quantum dot trafficking were determined by depleting Ca²⁺ in apical and basolateral bathing fluids of RAECM using 2 mM EGTA. Effects of temperature on quantum dot trafficking were studied by lowering temperature from 37°C to 4°C.

Results

Apical exposure of RAECM to quantum dots did not elicit changes in transmonolayer resistance or ion transport rate for up to 24 hours; quantum dot trafficking rates were not surface charge-dependent; methyl-β-cyclodextrin, chlorpromazine, and dynasore did not decrease quantum dot trafficking rates; lowering of temperature decreased transmonolayer resistance by approximately 90% with a concomitant increase in quantum dot trafficking by about 80%; and 24 hours of treatment of RAECM with EGTA decreased transmonolayer resistance by about 95%, with increased quantum dot trafficking of up to approximately 130%.

Conclusion

These data indicate that quantum dots do not injure RAECM and that quantum dot trafficking does not appear to take place via endocytic pathways involving caveolin, clathrin, or dynamin. We conclude that quantum dot translocation across RAECM takes place via both transcellular and paracellular pathways and, based on comparison with our prior studies, interactions of nanoparticles with RAECM are strongly dependent on nanoparticle composition and surface properties.

Keywords:

Acknowledgments

This work was supported in part by the Hastings Foundation, Whittier Foundation, and research grants (EY011386, EY017293, EY016985, ES017034, ES018782, HL038578, HL038621, HL062569, and HL089445) from the National Institutes of Health. Dr Crandall is Hastings Professor and Norris Chair of Medicine. Dr Borok is Edgington Chair in Medicine.

Disclosure

The authors report no conflicts of interest in this work.

Translocation of PEGylated quantum dots across rat alveolar epithelial cell monolayers

Background

Methods

Results

Conclusion

Information for

Open access

Opportunities

Help and information

Translocation of PEGylated quantum dots across rat alveolar epithelial cell monolayers

Abstract

Background

Methods

Results

Conclusion

Acknowledgments

Disclosure

Related research

To cite this article:

Download citation

Information for

Open access

Opportunities

Help and information

Keep up to date

Your download is now in progress and you may close this window

Login or register to access this feature