132
Chang et al. carried out meta-analysis to investigate toxicity of nano-TiO2 and its
potential harmful impact on human health. 62 of 375 articles were selected after
applying the inclusion criteria for the meta analysis study. Data were retrieved
in vitro and from short-time animal studies and according to included and excluded
criteria from 1994 to 2011. Different parameters for toxicity were used in cell, animal, and rat models, such as apoptotic and necrotic modifications, DNA damage,
genotoxicity, increases in cytokines IL-6 and IL-8, cytotoxicity and inflammation,
reactive oxygen species, apoptosis, lung toxicities and presence of aggregates or
agglomerates, liver DNA cleavage, and hepatocyte apoptosis. The combined toxic
effects of TiO2 nanoparticles were calculated by the different endpoints by cell and
animal models. They observed that more than 50% showed positive statistical significance except the apoptosis group. The cytotoxicity was in a dose-dependent but
was not clear in size-dependent manner (Chang et al. 2013).
5.4.1 Nanoparticles of Nonmetallic Substances
Carbon-Based Nanomaterials
Carbon-based nanomaterials are used in different sectors since they have limited
reactivity and wide surface area. They are stable and strong antioxidants. Among
them fullerenes and carbon nanotubes are widely used ones. It is shown that cytotoxicity of single-wall carbon nanotubes is higher than multiwall carbon nanotubes
(MWCNTs) in a study performed using a guinea pig alveolar macrophage. Singlewall carbon nanotubes considerably impaired phagocytosis of macrophages at low
dose (0.38μg/mL), while multiwall carbon nanotubes and C60 induced injury only
at a high dose (Jia et al. 2005). Solubility of fullerene derivatives are one of the key
parameters to show cytotoxicity. Single-wall carbon nanotubes were tested for toxicity on human embryo kidney cells (HEK293) and it was demonstrated that they
inhibit the proliferation of these cells by inducing cell apoptosis and decreasing
cellular adhesive ability (Chawla and Kumar 2013). When cells were exposed to
single-wall carbon nanotubes, toxic effects were found both dose-dependent and
time dependent manner and single-wall carbon nanotubes induce oxidative stress in
biological systems. In aquatic environment, single-wall carbon nanotubes have
toxic effects in fish such as gill irritation and brain injury. Studies indicated that
carbon nanotubes induce pulmonary toxicity and inflammation showed in mice
(Junyi 2015).
Reproductive toxicity of carbon nanotubes has been also investigated. Carbon
nanotubes studies of single-wall carbon nanotubes and double-wall carbon nanotubes biological effect on embryonic development of model species of Danio rerio
(zebrafish) reveal significant embryonic development inhibition but this effect
occurred with 2 times higher concentrations of double-wall carbon nanotubes
(Cheng et al. 2007). Fluorescently labeled multiwall carbon nanotubes injected to
Danio rerio embryos and they spread to the whole blastoderm. They did not show
any anomalies however the next generation of Danio rerio from multiwall carbon
B. Karahalil
Chang et al. carried out meta-analysis to investigate toxicity of nano-TiO2 and its
potential harmful impact on human health. 62 of 375 articles were selected after
applying the inclusion criteria for the meta analysis study. Data were retrieved
in vitro and from short-time animal studies and according to included and excluded
criteria from 1994 to 2011. Different parameters for toxicity were used in cell, animal, and rat models, such as apoptotic and necrotic modifications, DNA damage,
genotoxicity, increases in cytokines IL-6 and IL-8, cytotoxicity and inflammation,
reactive oxygen species, apoptosis, lung toxicities and presence of aggregates or
agglomerates, liver DNA cleavage, and hepatocyte apoptosis. The combined toxic
effects of TiO2 nanoparticles were calculated by the different endpoints by cell and
animal models. They observed that more than 50% showed positive statistical significance except the apoptosis group. The cytotoxicity was in a dose-dependent but
was not clear in size-dependent manner (Chang et al. 2013).
5.4.1 Nanoparticles of Nonmetallic Substances
Carbon-Based Nanomaterials
Carbon-based nanomaterials are used in different sectors since they have limited
reactivity and wide surface area. They are stable and strong antioxidants. Among
them fullerenes and carbon nanotubes are widely used ones. It is shown that cytotoxicity of single-wall carbon nanotubes is higher than multiwall carbon nanotubes
(MWCNTs) in a study performed using a guinea pig alveolar macrophage. Singlewall carbon nanotubes considerably impaired phagocytosis of macrophages at low
dose (0.38μg/mL), while multiwall carbon nanotubes and C60 induced injury only
at a high dose (Jia et al. 2005). Solubility of fullerene derivatives are one of the key
parameters to show cytotoxicity. Single-wall carbon nanotubes were tested for toxicity on human embryo kidney cells (HEK293) and it was demonstrated that they
inhibit the proliferation of these cells by inducing cell apoptosis and decreasing
cellular adhesive ability (Chawla and Kumar 2013). When cells were exposed to
single-wall carbon nanotubes, toxic effects were found both dose-dependent and
time dependent manner and single-wall carbon nanotubes induce oxidative stress in
biological systems. In aquatic environment, single-wall carbon nanotubes have
toxic effects in fish such as gill irritation and brain injury. Studies indicated that
carbon nanotubes induce pulmonary toxicity and inflammation showed in mice
(Junyi 2015).
Reproductive toxicity of carbon nanotubes has been also investigated. Carbon
nanotubes studies of single-wall carbon nanotubes and double-wall carbon nanotubes biological effect on embryonic development of model species of Danio rerio
(zebrafish) reveal significant embryonic development inhibition but this effect
occurred with 2 times higher concentrations of double-wall carbon nanotubes
(Cheng et al. 2007). Fluorescently labeled multiwall carbon nanotubes injected to
Danio rerio embryos and they spread to the whole blastoderm. They did not show
any anomalies however the next generation of Danio rerio from multiwall carbon
B. Karahalil