Safety issues relating to nanomaterials for construction applications - Nanotechnology in Eco-efficient Construction - page 131

Table 7.1 Overview of MNM classes and examples of properties which are
associated with toxicity responses to the respective MNM class and the
observed phenomenon or mode of action

MNM property
associated with
toxicity

Toxicological phenomenon
observed/mode of action MNM class

Metal Shedding heavy

metal (e.g., Ag,
Cu, Pt)

DNA cleavage and damage leading
to genotoxicity and mutation;
heavy metal ions induced
oxidative stress and infl ammatory
responses

Surface chemistries
that affect the
structure and
function of
proteins (e.g., Au)

Protein denaturation that may lead
to inactivation of hormones or
proteins, opening of cryptic
epitopes that could lead to
autoimmune diseases, protein
fi brillation and accumulation of
misfolded protein could lead to
disease conditions such as
Alzheimer's

Metal oxide Dissolution and

heavy metal
release (e.g., ZnO)

Heavy metal ions induced oxidative
stress and infl ammatory responses

Electron hole pair
generation during
photoactivation
(e.g., TiO 2 )

Electron hole pair generation during
photoactivation leading to free
radical generation

Silica particles Surface defects (e.g.,

SiO 2 )

Blood platelet, vascular endothelial
and clotting abnormalities

Metal
chalcogenide

Heavy metal release
(e.g., CdSe
quantum dots)

ROS generation, lipid peroxidation,
DNA damage

Fullerenes and
CNTs

Heavy metal
contamination,
aspect ratio >5

Fibrogenesis and tissue remodeling
injury, oxygen radical production,
GSH depletion, bio-catalytic
mechanisms

￿ ￿ ￿ ￿ ￿ ￿

Polymer Cationic charge

density

Membrane damage/leakage/thinning;
protein binding or unfolding
responses/denaturation of proteins
or fi brillation, lysosomal damage
through proton pump inactivation
or lysis of lysosomes