Biomedical Engineering Reference
In-Depth Information
matrices (mechanically and/or water-soluble) and/or more toxic fillers with higher
hydrous solubility, this observation may not be true.
The complete selection of NanoKem nanoparticles and sanding dusts were also
tested in vitro in primary human umbilical vein endothelial cells. The results were
in agreement with the in vivo results showing that sanding dusts were not more toxic
than sanding dusts from conventional paints (Mikkelsen et al. 2013).
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To the best of our knowledge the aforementioned publications are the only ones
testing the toxic effects of sanding dusts from nanoparticle-doped paints and lac-
quers. However, two other publications focusing on the toxic effects of other kinds of
nanocomposites have been published. Wohlleben and coworkers have published two
studies within this research area: (1) a study in rats testing toxic properties of sand-
ing dusts from cement and plastic with and without carbon nanotubes (Wohlleben
et al. 2011) and (2) an in vitro study using Precision Cut Lung Slices of sanding dust
from thermoplastic polyurethane with and without carbon nanotubes (Wohlleben
et al. 2013). The conclusions based on these studies are in agreement with the results
from the NanoKem study: No additional toxicity was observed for the nanoparticle-
containing products compared to the corresponding products without nanoparticles.
17.5 OUTLOOK
To summarize, a very limited number of published studies on the toxicological
effects of sanding dusts from nanocomposites, including the NanoKem study spe-
cifically testing silica in paint, lacquer, and binder, are in good agreement with each
other: No additional toxicity has been detected for any of the nanocomposites com-
pared to the corresponding composites without MN. Noteworthy, more results on
the emission characteristics and hazards of various process-generated dust emis-
sions from nanocomposites and reference materials, including paint dusts from a
recently completed FP7 project NanoSustain (www.nanosustain.eu), are currently
under preparation for publication. In this project, we investigated the effects of add-
ing nano-TiO
2
, CNTs, nano-ZnO, and nanocellulose to a range of products, including
paints, epoxy, paper, and a glass treatment product. As these MN and products have a
wider range of potential hazard and physicochemical matrix properties (e.g., hydrous
solubility and matrix integrity), the results from NanoSustain may add additional
valuable understanding of the emission characteristics and potential hazards associ-
ated with process-generated emissions from a wider range of nanocomposites.
For future work, it should be considered that all current studies have analyzed and
tested the total airborne dust generated during processing (e.g., sanding, grinding,
and cutting). It is observed that the composition of the dust varies with particle size.
Coarser particles are mainly paint fragments, whereas the smaller particles increas-
ingly consist of smaller paint aggregate fragments, fillers, and nanomaterials (Saber
et al. 2012c). It would be of high interest to investigate in greater detail the size-
fractioned dust from mechanical treatment processes. Additionally, it is necessary to
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