title: Size of TiO(2) nanoparticles influences their phototoxicity: an in vitro investigation.
abstract: To uncover the size influence of TiO(2) nanoparticles on their potential toxicity, the cytotoxicity of different-sized TiO(2) nanoparticles with and without photoactivation was tested. It was demonstrated that without photoactivation, TiO(2) nanoparticles were inert up to 100 μg/ml. On the contrary, with photoactivation, the toxicity of TiO(2) nanoparticles significantly increased, which correlated well with the specific surface area of the particles. Our results also suggest that the generation of hydroxyl radicals and reactive oxygen species (ROS)-mediated damage to the surface-adsorbed biomolecules could be the two major reasons for the cytotoxicity of TiO(2) nanoparticles after photoactivation. Higher ROS generation from smaller particles was detected under both biotic and abiotic conditions. Smaller particles could adsorb more proteins, which was confirmed by thermogravimetric analysis. To further investigate the influence of the generation of hydroxyl radicals and adsorption of protein, poly (ethylene-alt-maleic anhydride) (PEMA) and chitosan were used to coat TiO(2) nanoparticles. The results confirmed that surface coating of TiO(2) nanoparticles could reduce such toxicity after photoactivation, by hindering adsorption of biomolecules and generation of hydroxyl radical (·OH) during photoactivation.
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Sijing
authors.initials: S
authors.lastname: Xiong
authors.forename: Saji
authors.initials: S
authors.lastname: George
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Ji
authors.forename: Sijie
authors.initials: S
authors.lastname: Lin
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
authors.forename: Robert
authors.initials: R
authors.lastname: Damoiseaux
authors.forename: Bryan
authors.initials: B
authors.lastname: France
authors.forename: Kee Woei
authors.initials: KW
authors.lastname: Ng
authors.forename: Say Chye Joachim
authors.initials: SC
authors.lastname: Loo
mesh_terms: D000327:Adsorption; D000818:Animals; D002460:Cell Line / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry / Q000494:pharmacology; D020099:Coated Materials, Biocompatible / Q000633:toxicity; D017484:Dermatitis, Phototoxic; D017665:Hydroxyl Radical / Q000378:metabolism; D008298:Maleates / Q000737:chemistry / Q000494:pharmacology; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity* / Q000648:ultrastructure; D051379:Mice; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011095:Polyethylenes / Q000737:chemistry / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018675:Toxicity Tests / Q000379:methods; D014466:Ultraviolet Rays
chemical_list: D020099:Coated Materials, Biocompatible; D008298:Maleates; D011095:Polyethylenes; D011506:Proteins; D017382:Reactive Oxygen Species; D017665:Hydroxyl Radical; C007668:ethylene-maleic anhydride copolymer; D048271:Chitosan