CELL MEMBRANE INTEGRITY AND INTERNALIZATION OF INGESTED TiO_2 NANOPARTICLES BY DIGESTIVE GLAND CELLS OF A TERRESTRIAL ISOPOD

摘要

The present study was motivated by the paucity of reports on cellular internalization of ingested titanium dioxide (TiO_2) nanoparticles (nano-TiO_2). The model invertebrate (Porcellio scaber, Isopoda, Crustacea) was exposed to food dosed with nano-TiO_2 containing 100, 1,000, 3,000, or 5,000 jig nano-TiO_2 per gram of food. After 14dof exposure, the amount of Ti in the entire body was analyzed by inductively coupled plasma-mass 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-TiO_2 by the isopod's digestive gland epithelial cells was shown to depend on cell membrane integrity. Cell membranes were found to be destabilized by TiO_2 particles, and at higher extracellular concentrations of nano-TiO_2 the nanoparticles were internalized.