210
process and the assessment of stability of the nanodispersions, which should reach
a high monodispersity (Fangueiro et al. 2013).
The surface properties of NMs (i.e., surface area, chemistry and charge) will also
have a strong influence on their interaction with cellular membranes, which is considered a first step for induced cytotoxicity (Jo et al. 2015). Regarding surface
chemistry, NMs engineering often involves the performance of chemical modifications for surface functionalization. These modifications might have serious effects
on their toxicological profile once while some functional groups can offer greater
biocompatibility to NMs, on the other hand, their incorporation on the surface can
lead to greater toxic potential. Analytical techniques for NMs surface chemistry
determination are mainly the same, which were described for chemical composition
analysis (Surassmo et al. 2015). In terms of surface charge, zeta potential is the
property that is accessed, and it is crucial to always determine whether NMs are
positively or negatively charged. For instance, several reports have shown that positively charged NMs induced more toxic effects on cells than their negatively charged
counterparts (Bhattacharjee et al. 2013). Zeta potential is usually determined by
light-scattering electrophoresis or electro-acoustophoresis methodologies. Finally,
surface area and porosity can be determined by the Brunauer–Emmett–Teller analysis method, based on gas adsorption/desorption isotherms (Shin et al. 2015).
The crystallinity of NMs might also be a property with a relevant role in their
physicochemical and toxicological behaviors. Variations in chemical stability of
NMs may lead to different biological response and are correlated to the differences
in the orientation of the atoms. Information about the crystallographic structure of
NMs are mainly collected by XRD, which is the most common technique used to
define crystals pattern, position, intensity, and shape of the diffraction peaks (Kim
et al. 2014).
8.4 In Vitro Toxicological Assessment of Nanomaterials
Considering the previously commented challenging factors associated with the
interaction of NMs with biological systems, two different approaches may be applicable for nanotoxicity assessment, namely, (i) the commercially available kits that
make use of conventional in vitro protocols to evaluate a specific cellular endpoint
likely to be modified by the NMs under testing, and (ii) advanced analytical methods that assess specific toxicological effects of NMs. Gunsolus and Haynes
(Gunsolus and Haynes 2016) reviewed the most used analytical techniques in NM
toxicity research, taking into account the physicochemical properties of NMs and
their potential biological impact.
The use of cell cultures for the recording of toxicological endpoints evaluates
any physiological and/or biochemical changes induced by NMs (e.g., oxidative
stress promotion, inflammation induction), as well as the risk of cyto-/genotoxicity
(Love et al. 2012; Doktorovova et al. 2014a). Examples of the most common in vitro
M. C. Teixeira et al.
process and the assessment of stability of the nanodispersions, which should reach
a high monodispersity (Fangueiro et al. 2013).
The surface properties of NMs (i.e., surface area, chemistry and charge) will also
have a strong influence on their interaction with cellular membranes, which is considered a first step for induced cytotoxicity (Jo et al. 2015). Regarding surface
chemistry, NMs engineering often involves the performance of chemical modifications for surface functionalization. These modifications might have serious effects
on their toxicological profile once while some functional groups can offer greater
biocompatibility to NMs, on the other hand, their incorporation on the surface can
lead to greater toxic potential. Analytical techniques for NMs surface chemistry
determination are mainly the same, which were described for chemical composition
analysis (Surassmo et al. 2015). In terms of surface charge, zeta potential is the
property that is accessed, and it is crucial to always determine whether NMs are
positively or negatively charged. For instance, several reports have shown that positively charged NMs induced more toxic effects on cells than their negatively charged
counterparts (Bhattacharjee et al. 2013). Zeta potential is usually determined by
light-scattering electrophoresis or electro-acoustophoresis methodologies. Finally,
surface area and porosity can be determined by the Brunauer–Emmett–Teller analysis method, based on gas adsorption/desorption isotherms (Shin et al. 2015).
The crystallinity of NMs might also be a property with a relevant role in their
physicochemical and toxicological behaviors. Variations in chemical stability of
NMs may lead to different biological response and are correlated to the differences
in the orientation of the atoms. Information about the crystallographic structure of
NMs are mainly collected by XRD, which is the most common technique used to
define crystals pattern, position, intensity, and shape of the diffraction peaks (Kim
et al. 2014).
8.4 In Vitro Toxicological Assessment of Nanomaterials
Considering the previously commented challenging factors associated with the
interaction of NMs with biological systems, two different approaches may be applicable for nanotoxicity assessment, namely, (i) the commercially available kits that
make use of conventional in vitro protocols to evaluate a specific cellular endpoint
likely to be modified by the NMs under testing, and (ii) advanced analytical methods that assess specific toxicological effects of NMs. Gunsolus and Haynes
(Gunsolus and Haynes 2016) reviewed the most used analytical techniques in NM
toxicity research, taking into account the physicochemical properties of NMs and
their potential biological impact.
The use of cell cultures for the recording of toxicological endpoints evaluates
any physiological and/or biochemical changes induced by NMs (e.g., oxidative
stress promotion, inflammation induction), as well as the risk of cyto-/genotoxicity
(Love et al. 2012; Doktorovova et al. 2014a). Examples of the most common in vitro
M. C. Teixeira et al.