In Vitro Study for Nanomaterials - Nanotechnology and Human Health - page 162

be used as long as the stability and characterization of the suspension are
documented in detail so that experts can judge the toxicity of the substances
and estimate the hazardous level for human health. Of particular interest,
the unique physicochemical properties of some nanoparticles (e.g., carbon
nanotubes) create interferences with components of some cytotoxic assays,
leading to false conclusion on those nanoparticles' potential biosafety [34].
Therefore, several different methods are recommended to be used to vali-
date the in vitro nanotoxicity data.
Which metrics should be appropriate to measure the toxicity of nanopar-
ticles quantitatively is still a matter of argument. The toxicity of nanofibers
may be evaluated on the count concentration rather than mass concentration
because thin fibers can be more toxic than thick fibers. If nanoparticles are to
be dissolved, the mass concentration is more preferable because ionic forms
may be more toxic than insoluble forms. If the surface of nanoparticles is
highly reactive with biomolecules, the surface area is probably a more proper
measure for the toxicity.
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