Page 223 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

208 Principles and Methods

Hydrophobicity Aggregation
Surface Hydrophilicity Dispersability
reactivity Surface charge Solubility

Particle
size, surface Adsorption
area, shape tendency
Surface
chemistry
Crystallinity ROS &
oxidative Adverse
stress biological
effects/toxicity
Product
Surface coating/
chemicals

Chemical Durability
composition biopersistance
Figure 6.1 Particle-Related Characteristics Module. Nanoparticle physico-chemical
characterization can be divided into modules to clarify how primary, secondary, and
tertiary particle characteristics may lead to adverse biological effects. Adapted from [42].

membrane defects. This leads to the release of cellular enzymes that can
be assayed for [13]. Protein denaturation or degradation at the
organic/inorganic interphase can lead to functional or structural changes
in proteins at the primary, secondary, or tertiary level; this could man-
ifest as interference in enzyme function or exposure to antigenic sites
[14]. This damage may result from splitting of covalent bonds that are
responsible for protein structure, such as disulfide bonds (Figure 6.1).
There is also some evidence that certain nanoparticle characteristics
facilitate cellular uptake and access to the nucleus, where DNA damage
can result [15, 16]. In addition to this list of potential NM injuries, it is
conceivable that new material properties may emerge that could lead
to a new mechanism of toxicity.

Oxidative stress as a predictive paradigm
for ambient ultrafine particle toxicity
Although the manufacture of NM is a relatively new scientific develop-
ment, particle toxicity in response to ambient PM or mineral dust par-
ticles is a mature science. Animal exposure to these particles has shown
linkage of pulmonary inflammation to the ability of the particles to
induce ROS production and biologically relevant levels of oxidative