Environmental Engineering Reference
In-Depth Information
These magneto-pharmaceutical products were introduced for the first time as
contrast agents, used in magnetic resonance imaging, for localization and diagnos-
tic of brain injuries, myocardial infarction or liver lesions/tumors, where the
magnetic nanoparticles have a tendency to highly accumulate, due to differences
between tissue composition and endocytotoxic cellular processes [
140
-
143
].
Hyperthermia is a therapeutically procedure used for increasing body tempera-
ture in a certain region (between 41 and 46
C, especially in cancer therapy) [
144
-
149
]. This technique can be used together with other antitumor treatments (chemo-
therapy, radiotherapy, and immunotherapy).
Increasing the temperature required for hyperthermia can be accomplished using
fine iron oxide magnetic particles. Using an external magnetic field, these particles
can be transported and can target the tumor cells. The advantage of hyperthermia is
that induces heating of localized magnetic particles and the surrounding tissue,
which is enough for destroying the tumor cells, more sensitive to temperature
variations.
The first attempt for targeted drug therapy on humans was reported by L¨bbe
et al. [
150
], when they used magnetic nanoparticles coated with epirubicin [
151
] for
treatment of solid tumor. Treatment procedure consisted of intravenous infusion of
this mixture (magnetic nanoparticles coated with drug) followed by one cycle of
chemotherapy. During perfusion and 45 min after, a magnetic field was constructed
as close as possible to the tumor site, and they demonstrated that epirubicin-
carrying magnetic nanoparticles were successfully directed and transported toward
the tumor area.
Effectiveness of this therapy is dependent upon the intensity of magnetic field
and the properties of magnetic nanoparticles which are used. Dependent on admin-
istration route of drug-carrying magnetic nanoparticles (intravenous, intra-arterial),
a series of important parameters should be considered: blood flow, infusion path-
way, circulation time, distance from the magnetic source, strength of bound
between magnetic nanoparticle-drug, tumor volume, etc. [
128
,
152
].
7.3 Experimental Data
7.3.1
Introduction
In recent years, the design and synthesis of colloidal magnetic suspensions have
attracted an increased interest especially in the fields of biotechnology and bio-
medicine because they have many applications including targeted drug delivery,
cell labeling and magnetic cell separation, hyperthermia, tissue repairing, magnetic
resonance imaging (MRI) contrast enhancement, enzyme immobilization, immu-
noassays, protein purification, etc.
Magnetic nanoparticles (MNPs) used in biomedicine must meet several require-
ments. They have to be non-toxic, chemically stabile, uniform in size, well
