128
There are many studies conducted with econanoparticles to show their toxicity. A
pioneering study of Oberdörster (2004) showed that C60 fullerenes were inducing
changes in the brain of the fish already at very low aquatic exposure level. Namely,
significant lipid peroxidation was found in brains of largemouth bass after 48 h of
exposure to 0.5 mg/l of uncoated C60 fullerenes (tetrahydrofuran was used for solubilization of C60) (Oberdörster 2004).
Nanoparticles have been studied for cell toxicity, immunotoxicity, and genotoxicity. Human are exposed to various nanoscale materials since childhood, and the
new emerging field of nanotechnology has become another threat to human life
(Oberdörster et al. 2005a, b). Because of their small size, nanoparticles find their
way easily to enter the human body and cross the various biological barriers and
may reach the most sensitive organs. (Pourmand and Abdollahi 2012). Nanoparticles
can easily enter into the cells and membranes. They do accumulate in tissues;, therefore, they interact easily with cells via chemical reaction. They can be transferred
easily from one cell to another cell. As the result of this journey, they can induce the
increase of free radical and reactive oxygen species (ROS) caused by oxidative
stress due to their unique physicochemical characterization.
Although numerous studies have demonstrated different toxic effects associated
with nanomaterials such as oxidative stress, mitochondrial damage, chromosomal
aberrations and oxidative DNA damage, altered cell cycle regulation, and protein
denaturation, we still have little information on their toxicity mechanisms. One of
the most frequently suggested mechanisms about their toxicity is the production of
reactive oxygen species (ROS) and development of oxidative stress which are
responsible for damaging biomolecules such as DNA, RNA, proteins, and lipids
(Valdiglesias et al. 2015).
5.1.1 Toxicity of Nanoparticles
There has been an increasing public concern regarding the potential toxicity implications of nanoparticles. It is important to develop tests to evaluate the safety and
tolerability of nanoparticles after exposure of biological systems SCENIHR 2006.
When the possible toxicity of NPs take place after, commonly, inhalation or oral
intake, predominantly lung and gastroenteral toxicities studies have been investigated. Inhalation is a common route for exposure to nanomaterials. Thus, much
research has been performed on the pulmonary toxicity tests caused by nanoparticles.
5.1.2 Nanoparticles of Metallic Substances
The toxic effects of test substances are usually measured in terms of acute, subacute, subchronic or chronic exposure conditions. A maximum of 2 weeks (14 days),
a maximum of 4 weeks (28 days), a maximum of 13 weeks (90 days) and longer
B. Karahalil
There are many studies conducted with econanoparticles to show their toxicity. A
pioneering study of Oberdörster (2004) showed that C60 fullerenes were inducing
changes in the brain of the fish already at very low aquatic exposure level. Namely,
significant lipid peroxidation was found in brains of largemouth bass after 48 h of
exposure to 0.5 mg/l of uncoated C60 fullerenes (tetrahydrofuran was used for solubilization of C60) (Oberdörster 2004).
Nanoparticles have been studied for cell toxicity, immunotoxicity, and genotoxicity. Human are exposed to various nanoscale materials since childhood, and the
new emerging field of nanotechnology has become another threat to human life
(Oberdörster et al. 2005a, b). Because of their small size, nanoparticles find their
way easily to enter the human body and cross the various biological barriers and
may reach the most sensitive organs. (Pourmand and Abdollahi 2012). Nanoparticles
can easily enter into the cells and membranes. They do accumulate in tissues;, therefore, they interact easily with cells via chemical reaction. They can be transferred
easily from one cell to another cell. As the result of this journey, they can induce the
increase of free radical and reactive oxygen species (ROS) caused by oxidative
stress due to their unique physicochemical characterization.
Although numerous studies have demonstrated different toxic effects associated
with nanomaterials such as oxidative stress, mitochondrial damage, chromosomal
aberrations and oxidative DNA damage, altered cell cycle regulation, and protein
denaturation, we still have little information on their toxicity mechanisms. One of
the most frequently suggested mechanisms about their toxicity is the production of
reactive oxygen species (ROS) and development of oxidative stress which are
responsible for damaging biomolecules such as DNA, RNA, proteins, and lipids
(Valdiglesias et al. 2015).
5.1.1 Toxicity of Nanoparticles
There has been an increasing public concern regarding the potential toxicity implications of nanoparticles. It is important to develop tests to evaluate the safety and
tolerability of nanoparticles after exposure of biological systems SCENIHR 2006.
When the possible toxicity of NPs take place after, commonly, inhalation or oral
intake, predominantly lung and gastroenteral toxicities studies have been investigated. Inhalation is a common route for exposure to nanomaterials. Thus, much
research has been performed on the pulmonary toxicity tests caused by nanoparticles.
5.1.2 Nanoparticles of Metallic Substances
The toxic effects of test substances are usually measured in terms of acute, subacute, subchronic or chronic exposure conditions. A maximum of 2 weeks (14 days),
a maximum of 4 weeks (28 days), a maximum of 13 weeks (90 days) and longer
B. Karahalil