Biomedical Engineering Reference
In-Depth Information
9.2 TOXICOKINETICS IN THE BODY
Nanotechnology is a particularly exciting area of study due to the versatility of variable and adjust-
able parameters of nanomaterials, providing new approaches to the current challenges in medicine.
However, in order to fully materialize the potential benefits of nanotechnology, the risks have to
be appropriately identified and addressed. The flowthrough of nanotoxicity is understood to begin
with the route of exposure, where the physiochemical parameters of the nanomaterials determine
the types of molecular interactions and their distribution in the body, inducing toxicity and perhaps
even mutagenesis (Figure 9.2). At each of these components of nanotoxicity, it is imperative to
understand the factors inducing toxicity and regulate them appropriately, where the benefits are
maximized and the risks are minimized. The route of entry plays an important role in determin-
ing the distribution, metabolism, and interactions of the nanomaterials. Therefore, the limitation of
undesired effects of the nanoparticles can only be accomplished by the careful design of nanoma-
terial characteristics, with consideration to the route of exposure that could help target the desired
effect.
9.2.1 r
ole
of
the
r
oute
of
e
xposure
IN
t
oxIcIty
The exposure of nanoparticles to humans occurs usually through the dermal or inhalation routes.
Individuals who are most prone to exposure are most likely to be in a manufacturing or research
setting [42]. The literature provides strong evidence of the injurious effects of inhaled nanopar-
ticles. For example, a consistent correlation was seen between urban air pollution and a decrease
in expiratory peak flows in asthmatic patients along with impaired lung function in children [43].
Concerns have been raised over occupational safety for individuals exposed to asbestos [44], quartz
Respiratory
Skin
Digestive tract
Intravenous
Routes of
exposure
Size shape
Charge
Surface area
Composition
Solubility
Aggregation
Genotoxicity
Physiochemical
parameters
Receptors
Opsonization
Protein corona
Clearance
Molecular
interactions
Tumors
Liver
Kidneys
Brain
Distribution
ROS and NOS
Inflammatory
response
Neuro-inflammation
To xicity
Chromosomal
Abberations
Mutagenesis
FIGURE 9.2
(
See color insert.
) Concepts in nanotoxicology. The toxicity of nanomaterials is most com-
monly determined by the route of exposure and physiochemical parameters of the nanomaterials. Further, the
type of molecular interactions, based on the properties of the nanoparticle surface, define the distribution in
the body, and the extent and location of toxicity.
