78
as the nanorods coated with polystyrene or polyallamine (Asharani et al. 2011;
Böhme et al. 2015; Kim et al. 2013; Pan et al. 2013; Patibandla et al. 2018;
Ramachandran et al. 2017). Platinum nanoparticles are important environmental
pollutants that caused hatching delay, low heart rate, deformed spine, and anomalous
behavior of larvae after exposure during the embryonic age (Asharani et al. 2011).
The silver nanoparticles, widely present in commercial products, had a special
place in studies with the zebrafish embryonic test and represented more than 30% of
the study here considered. They reached the embryo crossing the chorion membrane
through the pores, with a passive mechanism sustained by Brownian movements.
Their toxicity involved all three endpoints, which are mortality, delayed hatching,
caudal fin malformation and low heart rate; 100% mortality followed the exposure
to 20 nM (Lee et al. 2007, 2012a, b, 2013b), while the ID50 for pericardial edema
was ca. 2 μg/ml, higher for axial malformations (Eryilmaz et al. 2018). Similar
results were also obtained in fish embryo test utilizing the medaka (Wu and Zhou
2012). The silver embryotoxicity was higher than that of gold, platinum, cadmium/
selenium, and zinc oxide (Asharani et al. 2011; Lacave et al. 2016). Several factors
influenced the toxicity of silver nanoparticles, such as the salinity of the water, the
shape of nanoparticles, their functionalization at the surface, the embryonic stage at
which the exposure started, and the presence of the chorion. Salt water was safer
than freshwater (Heinlaan et al. 2016), and nanoparticles shaped as plates were
more toxic than spheres or rods; moreover, the side effects of spheres totally
depended on the dissolved ions, while that of plates and rods, coated with polyvinylpyrrolidone, was due to the nanoparticles (van Pomeren et al. 2017b). The diffusion through the chorion was independent of the stage at which the embryo was
exposed, while the toxicity differed. The early gastrula and the hatched larvae were
resistant, while cardiac abnormalities developed after exposure at early and late
segmentation stage (0.02 nM). Then, exposure at the cleavage, pre-organogenesis
stage, caused multiple abnormalities of the spine, yolk sac edema, and acephaly
(Lee et al. 2013a). The functionalization at the surface with organic polymers did
not alter the passive crossing of the chorion (Lee et al. 2013b), while the toxicity
was differently affected. In general, neutral coating was safer, and negatively
charged more hazardous, but this is not a rule as pointed out by the various and rich
literatures in this field (Kim et al. 2013; Kim and Tanguay 2014; Lee et al. 2013b;
Orbea et al. 2017; Park et al. 2013; Powers et al. 2011; Truong et al. 2012).
Notwithstanding their proved toxicity, a study reported the exploitation of Ag
nanoparticles to imaging the segmentation of the zebrafish embryo. The nanoparticles were photostable, diluted in solution that remained stable for months, and had
plasmonic properties. Chorion revealed different zones of viscosity, and counterclockwise flow patterns (Nallathamby et al. 2008).
The health hazard of titanium dioxide nanoparticles, present in the formulation
of many commercial products, became also threatening as environmental pollutants.
Recently, a study tested the interaction of nanoparticles with a polymer used for
water remediation: the zebrafish embryo was grown in the presence of the Nafion
polymer combined with various fillers, such as anatase-type TiO 2 , without associated
lethal or sublethal effects (Pecoraro et al. 2018). The size of non-functionalized
A. G. Cattaneo
as the nanorods coated with polystyrene or polyallamine (Asharani et al. 2011;
Böhme et al. 2015; Kim et al. 2013; Pan et al. 2013; Patibandla et al. 2018;
Ramachandran et al. 2017). Platinum nanoparticles are important environmental
pollutants that caused hatching delay, low heart rate, deformed spine, and anomalous
behavior of larvae after exposure during the embryonic age (Asharani et al. 2011).
The silver nanoparticles, widely present in commercial products, had a special
place in studies with the zebrafish embryonic test and represented more than 30% of
the study here considered. They reached the embryo crossing the chorion membrane
through the pores, with a passive mechanism sustained by Brownian movements.
Their toxicity involved all three endpoints, which are mortality, delayed hatching,
caudal fin malformation and low heart rate; 100% mortality followed the exposure
to 20 nM (Lee et al. 2007, 2012a, b, 2013b), while the ID50 for pericardial edema
was ca. 2 μg/ml, higher for axial malformations (Eryilmaz et al. 2018). Similar
results were also obtained in fish embryo test utilizing the medaka (Wu and Zhou
2012). The silver embryotoxicity was higher than that of gold, platinum, cadmium/
selenium, and zinc oxide (Asharani et al. 2011; Lacave et al. 2016). Several factors
influenced the toxicity of silver nanoparticles, such as the salinity of the water, the
shape of nanoparticles, their functionalization at the surface, the embryonic stage at
which the exposure started, and the presence of the chorion. Salt water was safer
than freshwater (Heinlaan et al. 2016), and nanoparticles shaped as plates were
more toxic than spheres or rods; moreover, the side effects of spheres totally
depended on the dissolved ions, while that of plates and rods, coated with polyvinylpyrrolidone, was due to the nanoparticles (van Pomeren et al. 2017b). The diffusion through the chorion was independent of the stage at which the embryo was
exposed, while the toxicity differed. The early gastrula and the hatched larvae were
resistant, while cardiac abnormalities developed after exposure at early and late
segmentation stage (0.02 nM). Then, exposure at the cleavage, pre-organogenesis
stage, caused multiple abnormalities of the spine, yolk sac edema, and acephaly
(Lee et al. 2013a). The functionalization at the surface with organic polymers did
not alter the passive crossing of the chorion (Lee et al. 2013b), while the toxicity
was differently affected. In general, neutral coating was safer, and negatively
charged more hazardous, but this is not a rule as pointed out by the various and rich
literatures in this field (Kim et al. 2013; Kim and Tanguay 2014; Lee et al. 2013b;
Orbea et al. 2017; Park et al. 2013; Powers et al. 2011; Truong et al. 2012).
Notwithstanding their proved toxicity, a study reported the exploitation of Ag
nanoparticles to imaging the segmentation of the zebrafish embryo. The nanoparticles were photostable, diluted in solution that remained stable for months, and had
plasmonic properties. Chorion revealed different zones of viscosity, and counterclockwise flow patterns (Nallathamby et al. 2008).
The health hazard of titanium dioxide nanoparticles, present in the formulation
of many commercial products, became also threatening as environmental pollutants.
Recently, a study tested the interaction of nanoparticles with a polymer used for
water remediation: the zebrafish embryo was grown in the presence of the Nafion
polymer combined with various fillers, such as anatase-type TiO 2 , without associated
lethal or sublethal effects (Pecoraro et al. 2018). The size of non-functionalized
A. G. Cattaneo