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particles (Kahru and Dubourguier 2010). Three key elements of nanomaterials toxicity screening strategies have been outlined by Oberdörster et al. (2005a, b):
(1) Physicochemical characterization (size, surface area, shape, solubility, and
aggregation)
(2) Elucidation of biological effects involving in vitro (cellular and noncellular)
(3) In vivo studies (Oberdörster et al. 2005b)
Physicochemical characteristics of nanoparticles (solubility, surface area, chemical composition, etc.) have major impacts to show the toxicity. For example, poorly
soluble nanoparticles cause cancer and exhibit more toxicity. Greater potential hazard may relate to the surface area of nanoparticles compared with larger sized particles. Chemical composition and absorption rate on surface of nanoparticles have
important impact to show their toxicity. Size of nanoparticles is a key factor for
determining their toxicity. If the particle is very small, its surface area-to-volume
ratio is much greater and also chemical reactivity and biological activity are also
much higher. Aggregation of nanoparticles with cells, surface charges, and morphology of nanoparticles are important parameters for health effects (Viswanath
and Kim 2016).
The effects of nanoparticles have been studied on organisms such as algae and
fish. Two endpoints are used, namely, the biomarkers of effect and the biomarkers
of exposure, including growth and survival rate, mobility and reproduction. Dose,
distribution, bioavailability, fate and degradation of nanoparticles are used to assess
the exposure of nanoparticles. Risk assessment is very important for (1) creating
awareness of hazards and risk; (2) identifying organisms who may be at risk such as
fish; (3) determining existing control preventions or if needed further augment; (4)
determining whether a control program is required for a particular hazard; (5) providing data for legal regulations. Risk assessment is made by integration of hazard
identification, risk analysis, and risk evaluation. For risk assessment, available literature is searched from databases and has information on toxicity of nanoparticles.
A dose-response relationship is established by exposure information. Assessment of
exposure is analyzed by assays (in vitro tests; tissue and cell cultures, animal toxicity tests, and epidemiological studies) which are biomarker of exposure and biomarker of effect. These assays are applied to in vitro, in vivo, or cell cultures. Similar
studies are compared with each other; risk characterization is performed according
to the results from exposure to econanoparticles and biomarker evaluation. Thus, if
needed, protective preventions are taken and exposure are minimized or removed
CCOHS 2018; Kuempel et al. 2012). Due to the difficulty of conducting epidemiological studies, toxicological biomarkers in molecular epidemiology studies are
used more extensively in the risk characterization. For hazard identification of
nanoparticles and to demonstrate the toxicity of nanoparticles, cellular toxicity and
genotoxicity tests should be carried out. It is important to keep in mind that toxicity
assessments of nanoparticles because of their unique properties differ from largersized particles since these differences may cause problems in the conducting of
toxicity tests. Some technical problems may occur such as agglomeration and interactions between nanoparticles and biological cell components in different media.
5 Nanomaterials Causing Cellular Toxicity and Genotoxicity
particles (Kahru and Dubourguier 2010). Three key elements of nanomaterials toxicity screening strategies have been outlined by Oberdörster et al. (2005a, b):
(1) Physicochemical characterization (size, surface area, shape, solubility, and
aggregation)
(2) Elucidation of biological effects involving in vitro (cellular and noncellular)
(3) In vivo studies (Oberdörster et al. 2005b)
Physicochemical characteristics of nanoparticles (solubility, surface area, chemical composition, etc.) have major impacts to show the toxicity. For example, poorly
soluble nanoparticles cause cancer and exhibit more toxicity. Greater potential hazard may relate to the surface area of nanoparticles compared with larger sized particles. Chemical composition and absorption rate on surface of nanoparticles have
important impact to show their toxicity. Size of nanoparticles is a key factor for
determining their toxicity. If the particle is very small, its surface area-to-volume
ratio is much greater and also chemical reactivity and biological activity are also
much higher. Aggregation of nanoparticles with cells, surface charges, and morphology of nanoparticles are important parameters for health effects (Viswanath
and Kim 2016).
The effects of nanoparticles have been studied on organisms such as algae and
fish. Two endpoints are used, namely, the biomarkers of effect and the biomarkers
of exposure, including growth and survival rate, mobility and reproduction. Dose,
distribution, bioavailability, fate and degradation of nanoparticles are used to assess
the exposure of nanoparticles. Risk assessment is very important for (1) creating
awareness of hazards and risk; (2) identifying organisms who may be at risk such as
fish; (3) determining existing control preventions or if needed further augment; (4)
determining whether a control program is required for a particular hazard; (5) providing data for legal regulations. Risk assessment is made by integration of hazard
identification, risk analysis, and risk evaluation. For risk assessment, available literature is searched from databases and has information on toxicity of nanoparticles.
A dose-response relationship is established by exposure information. Assessment of
exposure is analyzed by assays (in vitro tests; tissue and cell cultures, animal toxicity tests, and epidemiological studies) which are biomarker of exposure and biomarker of effect. These assays are applied to in vitro, in vivo, or cell cultures. Similar
studies are compared with each other; risk characterization is performed according
to the results from exposure to econanoparticles and biomarker evaluation. Thus, if
needed, protective preventions are taken and exposure are minimized or removed
CCOHS 2018; Kuempel et al. 2012). Due to the difficulty of conducting epidemiological studies, toxicological biomarkers in molecular epidemiology studies are
used more extensively in the risk characterization. For hazard identification of
nanoparticles and to demonstrate the toxicity of nanoparticles, cellular toxicity and
genotoxicity tests should be carried out. It is important to keep in mind that toxicity
assessments of nanoparticles because of their unique properties differ from largersized particles since these differences may cause problems in the conducting of
toxicity tests. Some technical problems may occur such as agglomeration and interactions between nanoparticles and biological cell components in different media.
5 Nanomaterials Causing Cellular Toxicity and Genotoxicity