Cell membrane integrity and internalization of ingested TiO2 nanoparticles by digestive gland cells of a terrestrial isopod

The present study was motivated by the paucity of reports on cellular internalization of ingested titanium dioxide (TiO2) nanoparticles (nano-TiO2). The model invertebrate (Porcellio scaber, Isopoda, Crustacea) was exposed to food dosed with nano-TiO2 containing 100, 1,000, 3,000, or 5,000 mu g nano-TiO2 per gram of food. After 14?d of exposure, the amount of Ti in the entire body was analyzed by inductively coupled plasmamass spectrometry, and elemental analyses of tissue cross sections were performed by particle induced X-ray emission. In addition, a series of toxicological markers including feeding parameters, weight change, and survival, as well as cytotoxic effects such as digestive gland cell membrane stability, were monitored. Internalization of ingested nano-TiO2 by the isopod's digestive gland epithelial cells was shown to depend on cell membrane integrity. Cell membranes were found to be destabilized by TiO2 particles, and at higher extracellular concentrations of nano-TiO2, the nanoparticles were internalized. Environ. Toxicol. Chem. 2012; 31: 10831090. (c) 2012 SETAC