75
modified mouse embryonic stem cells, each of them expressing a green fluorescent
protein linked to a specific stress marker, is grown on a 96 well plate. Oxidative or
generic stress, protein unfolding, and DNA damage can be simultaneously monitored within the 24 hours required for the standard test. The validation was reached
for metal and metal oxide nanoparticles, while the carbon-based nanoparticles or
those present in diesel exhausts did not fulfill the standard. The nanoparticles oxides
of zinc, copper, and nickel were weakly embryotoxic (IC50 = 20 μg\ml), while
nickel nanoparticles were strongly embryotoxic (IC50 = 5 μg\ml). The embryotoxicity was accompanied by markers of oxidative stress and DNA damage. Other
nanoparticles including those of titanium dioxide, iron oxide, silver, and cerium
dioxide were safe and did not elicit expression of stress or damage markers. Diesel
exhaust and multiwalled carbon nanotubes were apparently safe, but the validation
was not obtained for these materials (Åkerlund et al. 2018; Karlsson et al. 2014).
In many cases, however, the studies tested only one cell line, and did not calculate the pharmacologic variables IC50 and ID50, this last being especially neglected.
Some strong embryotoxic compounds represented the exception to the otherwise
moderate or absent embryo toxicity of nanoparticles. Among them, the multiwalled
carbon nanotubes have limited general toxicity, but more pronounced genotoxicity
in mouse embryonic stem cells (Zhu et al. 2007a). Silver and titanium dioxide
attracted the main interest because of their diffuse exploitation for commercial
products. Cyto- and geno-toxicity were investigated. Silver induced irreversible
arrest of cell cycle, reduced expression of multipotency markers and morphological
changes. The cytotoxic effects were associated with signs of DNA damage, oxidative
stress, documented by hyper expression of specific markers and increased reactive
oxygen species. While coating with polysaccharide reduced the cytotoxicity, it
seemed not dependent on dissolution (Ahamed et al. 2008; Gao et al. 2017; Karlsson
et al. 2014; Park et al. 2011: Rajanahalli et al. 2015). The differentiation of female
embryonic stem cells was delayed after exposure to doses generally well tolerated
by male stem cells. The altered inactivation of one X chromosome, necessary to
start the differentiation, was indicated as the possible underlying mechanism (Zhang
et al. 2019).
The titanium dioxide nanoparticles was weakly cytotoxic for the human embryonic stem cells, with an IC50(24 h) = 50 μg/ml. The exposure induced DNA damage
through oxidative stress, apoptosis, altered proteome, and loss of multipotency and
of differentiation into cardiomyocytes. In 3 T3 fibroblasts, the compound was not
toxic, the adverse effects appeared only at concentration higher than 1000 μg/ml
and after long-term exposure. The toxicity of other oxide-based nanoparticles, such
as those of iron, zinc, nickel, silicon, was absent or weak (Demir et al. 2015; Farcal
et al. 2015; Krejcí et al. 2008; Pan et al. 2018; Park et al. 2009).
Gold nanoparticles were safely delivered inside the embryonic stem cells without affecting the viability and proposed as useful probe the embryonic stem cell
differentiation. Layers of nanogold organized in the nanoscale provided a safe
support for growing and maintaining the multipotency of mouse embryonic stem
cells (Lyu et al. 2004; Sathuluri et al. 2011).
3 Safety and Utility of Nanomaterials on Reproduction and Development: An Update…
modified mouse embryonic stem cells, each of them expressing a green fluorescent
protein linked to a specific stress marker, is grown on a 96 well plate. Oxidative or
generic stress, protein unfolding, and DNA damage can be simultaneously monitored within the 24 hours required for the standard test. The validation was reached
for metal and metal oxide nanoparticles, while the carbon-based nanoparticles or
those present in diesel exhausts did not fulfill the standard. The nanoparticles oxides
of zinc, copper, and nickel were weakly embryotoxic (IC50 = 20 μg\ml), while
nickel nanoparticles were strongly embryotoxic (IC50 = 5 μg\ml). The embryotoxicity was accompanied by markers of oxidative stress and DNA damage. Other
nanoparticles including those of titanium dioxide, iron oxide, silver, and cerium
dioxide were safe and did not elicit expression of stress or damage markers. Diesel
exhaust and multiwalled carbon nanotubes were apparently safe, but the validation
was not obtained for these materials (Åkerlund et al. 2018; Karlsson et al. 2014).
In many cases, however, the studies tested only one cell line, and did not calculate the pharmacologic variables IC50 and ID50, this last being especially neglected.
Some strong embryotoxic compounds represented the exception to the otherwise
moderate or absent embryo toxicity of nanoparticles. Among them, the multiwalled
carbon nanotubes have limited general toxicity, but more pronounced genotoxicity
in mouse embryonic stem cells (Zhu et al. 2007a). Silver and titanium dioxide
attracted the main interest because of their diffuse exploitation for commercial
products. Cyto- and geno-toxicity were investigated. Silver induced irreversible
arrest of cell cycle, reduced expression of multipotency markers and morphological
changes. The cytotoxic effects were associated with signs of DNA damage, oxidative
stress, documented by hyper expression of specific markers and increased reactive
oxygen species. While coating with polysaccharide reduced the cytotoxicity, it
seemed not dependent on dissolution (Ahamed et al. 2008; Gao et al. 2017; Karlsson
et al. 2014; Park et al. 2011: Rajanahalli et al. 2015). The differentiation of female
embryonic stem cells was delayed after exposure to doses generally well tolerated
by male stem cells. The altered inactivation of one X chromosome, necessary to
start the differentiation, was indicated as the possible underlying mechanism (Zhang
et al. 2019).
The titanium dioxide nanoparticles was weakly cytotoxic for the human embryonic stem cells, with an IC50(24 h) = 50 μg/ml. The exposure induced DNA damage
through oxidative stress, apoptosis, altered proteome, and loss of multipotency and
of differentiation into cardiomyocytes. In 3 T3 fibroblasts, the compound was not
toxic, the adverse effects appeared only at concentration higher than 1000 μg/ml
and after long-term exposure. The toxicity of other oxide-based nanoparticles, such
as those of iron, zinc, nickel, silicon, was absent or weak (Demir et al. 2015; Farcal
et al. 2015; Krejcí et al. 2008; Pan et al. 2018; Park et al. 2009).
Gold nanoparticles were safely delivered inside the embryonic stem cells without affecting the viability and proposed as useful probe the embryonic stem cell
differentiation. Layers of nanogold organized in the nanoscale provided a safe
support for growing and maintaining the multipotency of mouse embryonic stem
cells (Lyu et al. 2004; Sathuluri et al. 2011).
3 Safety and Utility of Nanomaterials on Reproduction and Development: An Update…