Biomedical Engineering Reference
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recovery period. Lung, lung-associated lymph nodes, and spleen were analyzed for
the test substance. The target concentrations were 2, 10, and 50 mg/m
3
.
The comparison of pulmonary toxicity of particles with different surface modifi-
cation showed particle type-dependent effects of the surface modification. The two
surface-modified ZrO
2
nanoparticles did not induce any adverse effects up to an
atmospheric concentration of 50 mg/m³. The switch of surface charge (see Table 1.2)
from strongly negative (acrylic acid) to neutral/positive (TODS) did not elicit signifi-
cant changes in the inhalation toxicity of ZrO
2
-based particles (Table 8.5), except for
a transient increase in neutrophils directly after exposure.
TABLE 8.5
Effects of 50 mg/m³ Metal Oxide Nanoparticles Observed in Short-Term
Inhalation Studies (nanoGEM) Directly after Exposure or after an Additional
3-Week Recovery Period
Property or
Effect
SiO
2
.
Naked
SiO
2
.
PEG
SiO
2
.
Amino
SiO
2
.
Phosph.
ZrO
2
.
Acryl
ZrO
2
.
TODS
Time Point
Units
Lung burden
After
exposure
µg/lung
343
836
743
500
169
694
After
recovery
µg/lung
209
371
475
304
190
521
Bronchoalveolar
fluid (BALF)
cell counts
After
exposure
Fold of
control
1.2
0.8
0.8
1.3
1
0.8
After
recovery
Fold of
control
1
1.1
0.9
1
0.9
0.6
BALF
neutrophils
After
exposure
Fold of
control
11.2**
2.3
4.2
2
1.3
8*
After
recovery
Fold of
control
21.8**
1
1.8
0.3
2.2
0.8
BALF
lymphocytes
After
exposure
Fold of
control
5.6**
1.8
1
3
3.8
1.4
After
recovery
Fold of
control
4.8**
0.7
2.4
0.6
0.7
0.5
Total protein
After
exposure
Fold of
control
1
1.1
0.7
1.1
1
0.8
After
recovery
Fold of
control
1.2
0.83
0.9
1.2
1.2
0.8
MCP-1 in
BALF
After
exposure
Fold of
control
0.9
1
1
1
1.1
1.7
After
recovery
Fold of
control
1.8
0.9
1.1
1
1
1.1
CINC-1/IL-8 in
BALF`
After
exposure
Fold of
control
1.2
1.2
0.8
1.1
0.7
1.7
After
recovery
Fold of
control
1.5
1
0.9
1.2
0.9
1.4
(
Continued
)
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