Biomedical Engineering Reference
In-Depth Information
(a)
(b)
a
b
a
b
Figure 6.12
Electron microscopy images
(original magnifi cation factor: 2.7
(6500) = 17 550) of HBT 3477 xenograft
tumors which had been excised from
the mice, at the time of sacrifi ce for
biodistribution study, 48 h post injection.
(a) Intact bioprobes can be seen on the
cancer cell surfaces (arrows), inferring cell
binding and retention; the nuclear membrane
and nucleolus are clearly seen in these
untreated cells; (b) Electron microscopy
image at 120 h after bioprobe injection, 48 h
after AMF treatment at 1300 Oe,
demonstrating substantial necrosis of the
cancer cells (a = nuclei of cells seen as
fragments; b = abundant cytoplasmic
vacuoles; c = disintegration of cell and nuclear
membranes). Reprinted with permission from
Ref. [139].
with external beam radiation treatment [190] . Therefore, tumor - specifi c magnetic
iron oxide nanoparticles may lead to advances in thermotherapy, thermochemo-
therapy and diagnostic imaging, or they may be combined as a so-called “theranos-
tic” approach [191]. The controlled release of drugs from heat-sensitive particle-drug
conjugates may also have the potential to reduce the adverse side effects of con-
ventional chemotherapeutic regimens.
6.4.1.4
MNP s - Directed Toxicity
The degradation of iron oxide nanoparticles
in vivo
is carried out via normal
metabolism, the natural pathways leading to an increased iron storage in the body.
Human tissues contain iron, iron oxides, ferritin, transferrin and hemosiderin for
