Environmental Engineering Reference
In-Depth Information
Nanoparticles (powdered/embedded in matrix)
Dispersion of nanoparticles (aerosol/suspension)
Routes of exposure and uptake into body (respiratory, gastrointestinal, dermal
exposure, parenteral exposure, translocation to distal sites-central nervous system)
Modication in the body (surface conditioning changes agglomeration/deagglomeration)
Distribution in the body (penetration of biological barriers, tissue and intracellular distribution)
Primary effect: inammation, generation of reactive oxygen species and interaction with
cellular components
Physical damage in lysosome; lipid peroxidation in vesicle; mitochondrial damage;
disruption of cell membrane; protein misfolding and oxidation; DNA damage.
Toxic effect (cytotoxicity and genotoxicity)
figurE 31.1
Biological effects of inorganic or metal-based nanoparticles.
effects of nanoparticles. interactions of nanoparticles with membranes depend largely on the nanoparticles' surface properties
and size. The nanoparticles' size is known to influence surface pressure and adhesion forces during interactions [44].
once internalized, nanoparticles interact with various cellular organelles and macromolecules present in the cell, resulting
in cytotoxic and genotoxic effects. cytoxicity leads to cell death as a result of membrane lipid peroxidation, membrane rupture,
energy depletion, or organelle destruction. genotoxicity occurs when adverse effects result at a genetic level and this can cause
cell death due to apoptosis and changes in interconnected signaling pathways [45].
Nanoparticles having the same size and magnitude as that of the protein molecules can interfere with cell signaling processes.
Nanoparticles interact with proteins, either by chaperone-like activity or by changing the configuration of proteins, leading to
protein misfolding [46].
Nanoparticle-DNA interaction has attracted special attention when assessing potential toxicological risks caused by nano-
materials. Nanoparticles can affect the genes either directly or indirectly, which is termed primary or secondary damage, respec-
tively. The mechanism of potential DNA damage by nanoparticles is still being understood. The main mechanism inducing
genotoxicity is the ability of the nanoparticles to produce oxidative stress. oxidative stress results due to the imbalance between
RoS and antioxidant conditions in the cell. Nanoparticles can intercalate or directly interact with DNA and cause mutagenicity
[47]. Apart from direct intercalation or physical and/or electrochemical interaction with nanoparticles, RoS production by
nanoparticles is again believed to play a major role in DNA damage [48]. RoS is responsible for oxidation of DNA bases, strand
breakage in DNA, and lipid peroxidation-mediated DNA adducts. in the primary mechanism, metal nanoparticles, depending
on their physicochemical properties, can directly produce oxidants, such as highly reactive hydroxyl radicals (oH
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and surface properties of nanoparticles also directly affect cell genotoxicity. it has been shown that small nanoparticles can
directly affect DNA by permeating into the cell nucleus. For example, the nanoparticles of titanium dioxide and silica are known
to penetrate the nucleus and cause intranuclear protein aggregates that can block vital cellular mechanisms such as replication, tran-
scription, and cell proliferation [49, 50]. The free metal ions generated from nanoparticles can also induce permeability of
nucleus barriers and indirectly damage DNA molecules. Nanoparticles can also stimulate mitochondria in cells to produce
RoS, which can destabilize the genetic material of the cells. in the secondary mechanism, nanoparticles can induce inflammatory
