Environmental Engineering Reference
In-Depth Information
Fig. 6.2 Nanoparticle surface and core-related parameters which might catalyze toxicological
interactions
there are limited analytical tools to predict about the intrinsic risks, tolerance,
hazards, toxicity, or dose-response relationships for almost all classes of
nanoparticles. One of the emerging fields in this direction is “Nanotolerance and
Nanotoxicology” which deals with constraints placed by the size and surface
properties toward toxicity by tracking properties of nanoparticle and their reactivity
in biological or physiological systems mainly by using in vitro assays. Attempts to
develop advance analytical tools and assays are still in primitive stages. These
critical determinants, discussed briefly here, include size, shape, particle surface,
surface positive charges, surface-containing groups, particle dissolution, metal ion
release from nanometals and nanometal oxides, UV light activation, aggregation,
mode of interaction with cells, inflammation, and pH of the medium.
These physico-chemical properties mainly affect the ultimate accumulation at
target site and also translocation of nanoparticles in body, e.g. nanoparticles admin-
istered to the lung can translocate to the liver, pulmonary accumulation of crystal-
line silica with accumulations in the liver, spleen, peritoneal cavity and bone
marrow. Surface contamination of biomaterials may range from adventitious
adsorption to surface oxidation, charge generation or initiation of electron transfer
reactions. The adventitious adsorption of bacteria-derived ubiquitous endotoxins—
pyrogens or lipopolysaccharides (LPS)—or polyaromatic hydrocarbons (PAHs—
known carcinogens) is one concern. Surface composition and its control are requi-
site to understand nanomaterial interactions with cells. Correct calculations of
biologically effective dose of nanoparticles based on mass or concentration of
particles per unit tissue or per number of cells or surface area of cells in cell culture
is very essential to get right dose-response relation and for toxicity predictions. The
