Biomedical Engineering Reference
In-Depth Information
RINP applications in various cancer models for imaging is provided in the follow-
ing subsection.
In these studies, SPIONs were conjugated to prepare Hepama-1, a humanized
monoclonal antibody linked to MNPs for the treatment of human liver cancer. A
direct method was used to radiolabel INPs with
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Re, with the radiolabeled INPs
subsequently demonstrating an effective killing of SMMC-7721 liver cancer cells.
It was suggested that such SPIONs might also be very useful for biomagnetically
targeted radiotherapy in liver cancer treatment [49].
Alpha(nu)beta(3) - targeted
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In-nanoparticles were developed and studied for the
detection of tumor angiogenesis [142]. Studies were conducted in New Zealand
White rabbits which had been implanted 12 days earlier with the Vx- 2 tumor.
Alpha(nu)beta(3)- targeted
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In-NPs bearing approximately 10
111
In per NP versus
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In per NP nuclide payloads were compared to nontargeted, radiolabeled control
particles.
In vivo
competitive binding studies were used to assess the ligand-
targeting specifi city. Alpha(nu)beta(3)-integrin-targeted NP with approximately 10
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In per NP provided a better tumor-to-muscle ratio contrast (6.3
±
0.2) than
approximately 1
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In per NP (5.1
±
0.1), or nontargeted particles with approxi-
mately 10
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In per NP (3.7
0.1), over the initial 2 h period after injection. After
18 h, the mean tumor activity in rabbits receiving alpha(nu)beta(3)-integrin-
targeted NP was fourfold higher than that in nontargeted controls (Figure 6.8).
Specifi city of the NP for the tumor neovasculature was supported by
in vivo
com-
petition studies and by fl uorescence microscopy of alpha(nu)beta(3)-targeted fl u-
orescence-labeled NP. Biodistribution studies revealed that, in rabbits, the primary
organ of clearance was the spleen. It would appear that alpha(nu)beta(3)- targeted
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In-NP may provide a clinically useful tool for the sensitive detection of angio-
genesis in tumors, particularly in combination with secondary high- resolution
imaging modalities, such as MRI [142] .
±
(a)
(b)
Tumor
Nontargeted
Targeted
Figure 6.8
The 18 - h
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In planar image (15 min scan,
128
×
128 matrix) of rabbits implanted 12 days previously
with Vx-2 tumor following 22 MBq kg
−
1
(i.v.) of nontargeted
(a) or
α
v
β
3
- targeted (b)
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In nanoparticles (NP) bearing
−
10
111
In per NP. Both images were windowed to have identical
dynamic ranges, as shown in (b). Reprinted with permission
from Ref. [142].
