Titanium Dioxide: Potential Toxic Effects on Human Intestinal Cells
Rafael, Shadi; Dalling, Kevin; Koeneman, Brian; and Capco, David
School of Life Sciences, Arizona State University
Nano-technology, involving particles less than 100 nm in size, has revolutionized a diverse array of industries as scientists and engineers design devices and materials that are superior in terms of speed, efficiency, and strength. Nanoparticles, which occur as the waste byproducts of nanodevices, can be released in the water during production accidents and ultimately accumulate in the drinking water. However, the effects of nanoparticles on the biological system have not been extensively studied. The purpose of this study was to determine the toxic effects of titanium dioxide nanoparticles on Caco-2, a human intestinal cell culture model. During the course of this study, Caco-2 cells were exposed to various concentrations of titanium dioxide in vitro, for the duration of 24-hours or two weeks. A variety of methods such as trans-epithelial electrical resistance (TEER) measurements, live/dead staining, and inspection of cell junctions using confocal microscopy were used to examine the integrity of the cells after exposure to the nanoparticles. TEER was primarily employed to monitor the presence and condition of the epithelial tissue since the electrode resistance measurements exhibit directly the degree of confluence of the cellular monolayer. Immunocytochemistry that utilizes antibodies as markers of cellular antigens also was used in distinguishing live and dead cells, as well as, in examining the location of c-catenin and ZO-1 proteins, which are responsible for adherens junctions and tight junctions of a cell respectively.