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Colloids Surf B Biointerfaces. 2019 Jan 1;173:148-154. doi: 10.1016/j.colsurfb.2018.09.050. Epub 2018 Sep 21.

Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane.

Author information

1
Institute of Fine Chemistry and Nanochemistry, Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus Universitario de Rabanales, Edificio Marie Curie, Córdoba, E-14014, Spain.
2
Biofisika Institute (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country UPV/EHU, 48940, Leioa, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, 48011, Spain.
3
CIC biomaGUNE, 20014, San Sebastian, Spain; Center for Research in Biological Chemistry and Molecular Materials (CiQUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain. Electronic address: carolina.carrillo@usc.es.
4
Institute of Fine Chemistry and Nanochemistry, Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus Universitario de Rabanales, Edificio Marie Curie, Córdoba, E-14014, Spain. Electronic address: jjginer@uco.es.

Abstract

Fluorescent inorganic quantum dots are highly promising for biomedical applications as sensing and imaging agents. However, the low internalization of the quantum dots, as well as for most of the nanoparticles, by living cells is a critical issue which should be solved for success in translational research. In order to increase the internalization rate of inorganic CdSe/ZnS quantum dots, they were functionalized with a fluorinated organic ligand. The fluorinated quantum dots displayed an enhanced surface activity, leading to a significant cell uptake as demonstrated by in vitro experiments with HeLa cells. We combined the experimental and computational results of Langmuir monolayers of the DPPC phospholipid as a model cell membrane with in vitro experiments for analyzing the mechanism of internalization of the fluorinated CdSe/ZnS quantum dots. Surface pressure-molecular area isotherms suggested that the physical state of the DPPC molecules was greatly affected by the quantum dots. UV-vis reflection spectroscopy and Brewster Angle Microscopy as in situ experimental techniques further confirmed the significant surface concentration of quantum dots. The disruption of the ordering of the DPPC molecules was assessed. Computer simulations offered detailed insights in the interaction between the quantum dots and the phospholipid, pointing to a significant modification of the physical state of the hydrophobic region of the phospholipid molecules. This phenomenon appeared as the most relevant step in the internalization mechanism of the fluorinated quantum dots by cells. Thus, this work sheds light on the role of fluorine on the surface of inorganic nanoparticles for enhancing their cellular uptake.

KEYWORDS:

Fluorination; Langmuir monolayers; Quantum dots; Uptake

PMID:
30286431
DOI:
10.1016/j.colsurfb.2018.09.050
[Indexed for MEDLINE]

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