Spectroscopy – Inductively Coupled Plasma Mass Spectrometry
Elemental bioimaging of Al
2
O
3
/ZrO
2
/TiO
2
nanoparticles
in lung tissue
Jennifer-Christin Müller
1
, Michael Sperling
1
, Uwe Karst
1
1
Institute of Inorganic and Analytical Chemistry, University of Münster,
Germany
■ Introduction
Nanotechnology is one of the key developments of
the 21
st
century. Nanoparticles are used in a wide
variety of industrial, military and medical
applications. Titanium dioxide (TiO
2
) nanoparticles
are one of the most frequently used nanomaterials,
for example in sunscreens as UV blocker or as
antibacterial textile coating. Aluminum oxide
(Al
2
O
3
) nanoparticles are used as abrasion-
resistant coating in the automobile industry. In
addition to that, grinding dusts can contain Al
2
O
3
as well as zirconium dioxide (ZrO
2
) nanoparticles.
Because of the small diameter, the nanoparticles
can enter the body through the lungs and are able
to cause inflammation or cell defects in the lung
tissue. To be able to assess the long-term toxicity
of nanoparticles, the distribution in affected organs
plays an important role. Elemental bioimaging by
means of laser ablation-inductively coupled
plasma-mass spectrometry (LA-ICP-MS) is a
useful tool to analyze various elements in tissue
sections. Here, the distribution and concentration
of mixed oxide nanoparticles in rat lung tissue was
analyzed.
■ Material and methods
Animal study
The animal study and organ preparation were
performed by IBE R&D gGmbH. The used
nanoparticles were composed of aluminum(III)
oxide (77% w/w), zirconium(IV) dioxide (12% w/w)
and titanium(IV) dioxide (11% w/w) with a d50
value of approx. 35 nm. The nanoparticles were
intratracheally instilled into the left lung in 0.9%
sodium chloride solution with an addition of
0.025 mg/ml lecithin. The instilled nanoparticle
concentration was 4.8 mg per lung. The rats were
euthanized three days after the instillation. The
lungs were filled with an embedding media to
avoid collapsing of the organ and snap-frozen
afterwards. Tissue sections with a thickness of
10 μm were prepared using a cryotome and
subsequently mounted on a microscope slide.
Standard preparation
To quantify the nanoparticle concentration in the
lung, an external calibration with matrix-matched
standards was performed. Gelatin (10% w/w) was
spiked the nanoparticle dispersion to obtain
standards with different aluminum, titanium and
zirconium concentrations. Thin sections with the
same thickness as the tissue sample were
prepared and analyzed with the same
measurement parameters.
Analytical conditions
For elemental bioimaging of tissue samples, LA-
ICP-MS is the analytical method of choice. Here,
the ICPMS-2030 quadrupole mass spectrometer
was coupled to a laser ablation system LSX-213
G2
+
(Teledyne CETAC). The system was equipped
with a Nd-YAG laser operating at a wavelength of
213 nm. The laser ablation was connected to the
ICP-MS via Tygon
®
tubing attached to the
expansion pipe. The ablation cell was flushed with
helium.
No. SCA-116-003
