RESUMO
Titanium dioxide nanoparticles (TiO2 NPs) are massively produced and widely used in daily life, which may pose potential risk to human health via uncharacterized interaction between DNAs. This research aims to examine the interaction between DNA and three types of TiO2 NPs of different sizes and crystallines. The interaction between TiO2 NPs and liver DNA molecules obtained from Sprague-Dawley rats was systematically evaluated in vivo using atomic force microscopy, transmission electron microscopy, various spectroscopic techniques and gel electrophoresis. We found that TiO2 NPs (diameter <25 nm and <100 nm) in anatase crystalline can covalently interact with liver DNA by either inserting itself in between DNA base pairs or binding to DNA nucleotide via P-O-Ti-O bond. Such interaction may not be NP size-dependent but may be crystalline phase-dependent, because such interaction did not occur in rutile crystal phase, in which the DNA damage was potentially caused by reactive oxygen species.
Assuntos
DNA/efeitos dos fármacos , Fígado/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Animais , DNA/química , DNA/metabolismo , Eletroforese em Gel de Ágar , Histocitoquímica , Fígado/química , Fígado/metabolismo , Nanopartículas Metálicas/química , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Conformação de Ácido Nucleico , Tamanho da Partícula , Ratos , Ratos Sprague-Dawley , Titânio/química , Titânio/metabolismoRESUMO
Titanium dioxide nanoparticles are massively produced and widely used in daily life, which has posed potential risk to human health. However, the molecular mechanism of TiO(2) nanoparticles (NPs) with different crystal phases is not clear. In this study, the characterization of two crystalline phases of TiO(2) NPs is evaluated by transmission electron microscopy and X-ray absorption fine structure spectrum; an interaction of these TiO(2) NPs with HaCaT cells is studied in vitro using transmission electron microscopy, chemical precipitation method, and X-ray absorption fine structure spectrometry. The coordination and surface properties indicate that only the anatase-TiO(2) NPs allow spontaneous reactive oxygen species (ROS) generation, but rutile-TiO(2) NPs do not after dispersion. The interaction between TiO(2) NPs and cellular components might also generate ROS for both anatase-TiO(2) NPs and rutile-TiO(2) NPs. The ROS generation could lead to cellular toxicity if the level of ROS production overwhelms the antioxidant defense of the cell or induces the mitochondrial apoptotic mechanisms. Furthermore, Ti had a direct combination with some protein or DNA after NPs enter the cell, which could also lead to cellular toxicity.
