FRÖHLICH Eleonore Medical University of Graz

In-Vitro Testing for Identification of Long-term Effects of Nanoparticles

Co-authors MEINDL Claudia, MRAKOVCIC Maria, LEITINGER Gerd, BAUMGARTNER Ramona, ROBLEGG Eva

Human exposure to nanoparticles increases because nano-sized materials are included in food, consumer and medicinal products, as well as being present in the environment. Routine cytotoxicity screening evaluates effects only upon acute exposure, usually 24h, but prolonged contact with nanoparticles might result in intracellular accumulation and disturbance of cell function. We studied effects of polystyrene particles, carbon nanotubes, and silica nanoparticles on endothelial cells and on monocytes using various culturing systems (microcarrier, CELLine CL350, and sub-culturing) for up to 28d. Particles were physicochemically characterized, cellular uptake studied, and functional assays for lysosomes as potential organelles for accumulation effects, applied. Nanoparticles formed aggregates to different extent and after cellular uptake were accumulated in lysosomes. Cytotoxicity after long-term exposure was higher than after acute exposure but adaptation to nanoparticle damage was also seen. Differences between acute and long-term exposure were greater for less cytotoxic particles and for less sensitive cell lines. Disruption of membrane integrity and induction of apoptosis played a role in the long-term cytotoxic effect of the particles with stronger acute cytotoxicity. Accumulation of nanoparticles at non-cytotoxic doses in lysosomes did not have a prominent effect on their function.

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