Fluorinated CdSe/ZnS quantum dots: Interactions with cell membrane

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 173; pp. 148 - 154
• Main Authors: Argudo, Pablo G., Martín-Romero, María T., Camacho, Luis, Carril, Mónica, Carrillo-Carrión, Carolina, Giner-Casares, Juan J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2019
• Subjects: 1,2-Dipalmitoylphosphatidylcholine - analogs & derivatives; 1,2-Dipalmitoylphosphatidylcholine - chemistry; Cadmium Compounds - chemistry; Cadmium Compounds - pharmacology; Cell Membrane - chemistry; Cell Membrane - drug effects; Cell Membrane - metabolism; Cell Survival - drug effects; Endocytosis; Fluorination; Halogenation; HeLa Cells; Humans; Hydrophobic and Hydrophilic Interactions; Kinetics; Langmuir monolayers; Molecular Dynamics Simulation; Quantum dots; Quantum Dots - chemistry; Selenium Compounds - chemistry; Selenium Compounds - pharmacology; Sulfides - chemistry; Sulfides - pharmacology; Thermodynamics; Unilamellar Liposomes; Uptake; Zinc Compounds - chemistry; Zinc Compounds - pharmacology; Fluorination; Langmuir monolayers; Quantum dots; Uptake
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2018.09.050

[Display omitted] •Efficient uptake of inorganic nanoparticles hinders their application biomedicine.•Fluorinated ligands are a promising strategy for enhancing the cell uptake.•Experimental and computational studies describe the interaction with membrane.•Hydrophobicity provided by the fluorine atoms is key in the uptake. 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.