Spark generated particles for nanotoxicology studies
M.E. Messing1, C.R. Svensson2, B.O. Meuller1, M. Bohgard2, K. Deppert1, J. Pagels2 and J. Rissler2
1
Solid State Physics, Lund University, Lund, 221 00, Sweden
Ergonomics and Aerosol Technology, Lund University, Lund, 221 00, Sweden
Keywords: spark discharge, aerosol particle mass analyzer, nanotoxicology, health effects of aerosols.
Presenting author email: maria.messing@ftf.lth.se
2
During the last decade there has been an explosion in
novel applications and products based on nanoparticles.
Although the belief in the great potential of nanoparticles
is strong, major concerns with respect to their toxicology
have been frequently discussed lately. It is well known
that the properties of a specific nano-sized material are
different from the properties of the same material in bulk
form, and therefore toxicology regulations often based
on mass might not be relevant for nano-sized materials.
In order to improve the understanding of nanotoxicology
and to learn how to handle nanoparticles in a safe way it
is of utmost importance to use highly characterized
nanoparticles for toxicology investigations.
In the present contribution we describe a route to
generation and deposition of very well characterized
nanoparticles with respect to size, shape, mass, surface
area and crystal structure. The nanoparticles were
generated by spark discharge and fed into an aerosol
nanoparticle system setup (Messing et al., 2009) for online characterization, reshaping and deposition. Tandem
differential mobility analyzers (DMA) coupled to an
electrometer was used for mobility diameter and number
concentration measurements. The particle mass was
measured with a DMA-aerosol particle mass analyzer
(DMA-APM) coupled to a condensation particle counter
(CPC). An electrostatic precipitator was used for
controlled particle deposition onto lacy carbon film
coated Cu transmission electron microscopy (TEM)
grids as well as directly into protein solutions. Primary
particle size as well as particle shape and crystal
structure were evaluated by TEM. Particle surface area
was calculated from the measured primary particle size
combined with either the DMA-APM measurements or
the idealized aggregate theory (IA) approach. Finally the
deposited mass and surface area dosages were calculated
for deposition in an air liquid interface (ALI) chamber
(Savi et al., 2008) or the alveolar region of the
respiratory tract.
Gold particles were used to demonstrate the
capability of the setup, although particles of other
materials can easily be produced by changing the
electrode material in the spark discharge generator
(Tabrizi et al., 2009). From the measurements and
calculations it is clear that a high enough mass and
surface area reported for onset of inflammatory response
can be reached in the ALI chamber, if a deposition time
of roughly two hours is used. A further key aspect of the
setup is the possibility to use a sintering furnace to
reshape the as-produced agglomerate particles (Figure
1). By using this approach particles of the same number
concentration and mass, but with clearly different
surface area can be deposited. This provides for a direct
comparison of toxicological response upon surface area,
a feature that is believed to play a major role in
nanoparticle toxicity. Finally, Dynamic Light Scattering
(DLS) showed that when gold particles were deposited
into protein solutions, the suspensions were stable for
several days, which is promising for future studies.
Figure 1. Gold nanoparticles of the same mass (0.24 fg)
(a) before and (b) after reshaping. The mobility diameter
decreased from 60 to 31 nm upon reshaping.
This work was supported by the Nanometer Structure
Consortium at Lund University (nmC@LU) and the
Swedish research council FAS through project 20091291 and the FAS-centre METALUND.
Messing, M.E. et al. (2009) Gold Bull. 42, 20-26.
Savi, M. et al. (2008) Environ. Sci. Technol. 42, 566774.
Tabrizi, N.S. et al. (2009) J. Nanopart. Res. 11, 315-32.