J toxicol Sci 2009 Oct;34(4):363-75.

Cytotoxicity of nanoparticles independent from oxidative stress.

Fröhlich E, Samberger C, Kueznik T, Absenger M, Roblegg E, Zimmer A, Pieber TR.
Center for Medical Research, Medical University of Graz, A-8010 Graz, Austria.
eleonore.froehlich@...

The use of nano-sized materials offers exciting new options in technical and
medical applications. On the other hand, adverse effects on cells have been
reported and may limit their use. In addition to physico-chemical parameters
such as contamination with toxic elements, fibrous structure and high surface
charge, the generation of radical species was identified as key mechanism for
cytotoxic action of nanoparticles. The cytotoxic potential of nanoparticles in
the absence of radical generation is less well investigated. This study aims to
investigate the size-dependent effect of carboxyl polystyrene particles on cells
to identify potential adverse effects of these particles. Particles were
characterized in different solutions to assess the influence of the medium on
size and surface charge. Viability, membrane integrity, apoptosis, proliferation
and generation of oxidative stress were investigated. In addition the
intracellular localization of the particles was recorded. 20 nm polystyrene
particles induced cellular damage by induction of apoptosis and necrosis. These
particles generated radicals to the same degree as larger polystyrene particles.
Particles were taken up into endosomes and lysosomes in a size-dependent manner.
Protein containing solutions led to increases in particle size, decreased
cytotoxicity and reduced cellular uptake. It can be concluded that even in the
absence of high surface reactivity and not linked to the generation of radicals
nano-sized particles may cause cell damage. The mechanism of this damage
includes apoptosis, necrosis and inhibition of proliferation.
PMID: 19652459 [PubMed - indexed for MEDLINE]