Effects of the physicochemical properties of titanium dioxide nanoparticles, commonly used as sun protection agents, on microvascular endothelial cells.
Until now, the potential effects of titanium dioxide (TiO2) nanoparticles on endothelial cells are not well understood, despite their already wide usage. Therefore, the present work characterizes six TiO2nanoparticle samples in the size range of 19 × 17 to 87 × 13 nm, which are commonly present in sun protection agents with respect to their physicochemical properties (size, shape, ζ-potential, agglomeration, sedimentation, surface coating, and surface area), their interactions with serum proteins and biological impact on human microvascular endothelial cells (relative cellular dehydrogenase activity, adenosine triphosphate content, and monocyte chemoattractant protein-1 release). We observed no association of nanoparticle morphology with the agglomeration and sedimentation behavior and no variations of the ζ-potential (-14 to -19 mV) in dependence on the surface coating. In general, the impact on endothelial cells was low and only detectable at concentrations of 100 μg/ml. Particles containing a rutile core and having rod-like shape had a stronger effect on cell metabolism than those with anatase core and elliptical shape (relative cellular dehydrogenase activity after 72 h: 60 vs. 90 %). Besides the morphology, the nanoparticle shell constitution was found to influence the metabolic activity of the cells. Upon cellular uptake, the nanoparticles were localized perinuclearly. Considering that in the in vivo situation endothelial cells would come in contact with considerably lower nanoparticle amounts than the lowest-observable adverse effects level (100 μg/ml), TiO2nanoparticles can be considered as rather harmless to humans under the investigated conditions.
Department of Experimental Radiology, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital-Friedrich Schiller University Jena, Erlanger Allee 101, 07747 Jena, Germany.
Claudia
C
Strobel
Department of Chemistry and Center for NanoScience (CeNS), University of Munich (LMU), Butenandtstraße 5-13 (E), 81377 Munich, Germany.
Adriano A
AA
Torrano
Department of Physics, University of Augsburg, Universitaetsstraße 1, 86159 Augsburg, Germany.
Rudolf
R
Herrmann
Physical Chemistry, University of Duisburg-Essen, Universitaetsstraße 5-7, 45117 Essen, Germany.
Marcelina
M
Malissek
Department of Chemistry and Center for NanoScience (CeNS), University of Munich (LMU), Butenandtstraße 5-13 (E), 81377 Munich, Germany.
Christoph
C
Bräuchle
Department of Physics, University of Augsburg, Universitaetsstraße 1, 86159 Augsburg, Germany.
Armin
A
Reller
Physical Chemistry, University of Duisburg-Essen, Universitaetsstraße 5-7, 45117 Essen, Germany ; Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany ; Institut für Mikrotechnik Mainz GmbH, Carl-Zeiss-Str. 18-20, 55129 Mainz, Germany.
Lennart
L
Treuel
Department of Experimental Radiology, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital-Friedrich Schiller University Jena, Erlanger Allee 101, 07747 Jena, Germany.
Ingrid
I
Hilger
Endothelial cells; Environmental and health effects; Nanoparticle; Nanotoxicology; Sun protection agent; Titanium dioxide