title: Stiffness alterations of single cells induced by UV in the presence of nanoTiO2.
abstract: Nanocrystalline titanium dioxide (nanoTiO2) has been reported to generate reactive oxygen species (ROS) under UV illumination. In our studies, changes in mechanical properties of human skin fibroblasts, exposed to the oxidative stress induced in the presence of nanoTiO2 and UV light, were studied using atomic force microscopy (AFM). The exposure of cells to the action of ROS was performed at low TiO2 concentration (4 microg/mL) and under illumination with low-intensity UVA (8 and 20 mW/cm2) or UVC (0.1 mW/ cm2). AFM measurements of the cell stiffness were carried out immediately after exposure of cells to the oxidative stress. The data suggest that under illumination with low-intensity UVA nanoTiO2 generates ROS, which, in turn, damage cellular and subcellular structures. This process was detected by AFM as a marked drop in the cellular stiffness of ca. 30-75%, which occurred rapidly, in the time frame of 1 min. The photo-oxidative stress inducing the decrease of cell stiffness was cancelled in the presence of a well-established antioxidant, beta-carotene. The results highlight the sensitivity of AFM to detect early changes in mechanical properties of cells exposed to oxidative stress.
authors: Institute of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors: Bertrand
authors: B
authors: Vileno
authors: Małgorzata
authors: M
authors: Lekka
authors: Andrzej
authors: A
authors: Sienkiewicz
authors: Sylvia
authors: S
authors: Jeney
authors: Gabriela
authors: G
authors: Stoessel
authors: Janusz
authors: J
authors: Lekki
authors: László
authors: L
authors: Forró
authors: Zbigniew
authors: Z
authors: Stachura
mesh_terms: D006801:Humans; D053768:Metal Nanoparticles; D018625:Microscopy, Atomic Force; D017382:Reactive Oxygen Species; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D017382:Reactive Oxygen Species; C009495:titanium dioxide; D014025:Titanium