Current cancer therapies are highly cytotoxic and their delivery to exclusively the affected site
is poorly controlled, resulting in unavoidable and often severe side effects. In an effort to overcome
such issues, magnetic nanoparticles have been recently gaining relevance in the areas of biomedical
applications and therapeutics, opening pathways to alternative methods. This led to the concept of
magnetic particle hyperthermia in which magnetic nano beads are heated by a high power magnetic
field. The increase in temperature kills the cancer cells, which are more susceptible to heat in
comparison to healthy cells.
In this dissertation, the possibility to kill cancer cells with magnetic nanowires is evaluated.
The idea is to exploit a magnetomechanical effect, where nanowires cause cancer cell death through
vibrating in a low power magnetic field. Specifically, the magnetic nanowires effects to cells in culture
and their ability to induce cancer cell death, when combined with an alternating magnetic field, was
Nickel and iron nanowires of 35 nm diameter and 1 to 5 μm long were synthesized by electrodeposition
into nanoporous alumina templates, which were prepared using a two-step anodization
process on highly pure aluminum substrates. For the cytotoxicity studies, the nanowires were added
to cancer cells in culture, varying the incubation time and the concentration. The cell-nanowire
interaction was thoroughly studied at the cellular level (mitochondrial metabolic activity, cell membrane
integrity and, apoptosis/necrosis assay), and optical level (transmission electron and confocal
microscopy). Furthermore, to investigate their therapeutic potential, an alternating magnetic field
was applied varying its intensity and frequency. After the magnetic field application, cells health
was measured at the mitochondrial activity level.
Cytotoxicity results shed light onto the cellular tolerance to the nanowires, which helped in
establishing the appropriate nanowire concentrations to use the nanowires + alternating magnetic
field combination as a cancer treatment. Different levels of cancer cell death were achieved by
changing the incubation time of the nanowires with the cells and the alternating magnetic field
parameters. Cell viability was significantly affected in terms of mitochondrial activity and cell
membrane integrity after applying the treatment (nanowires + alternating magnetic field) using a
low-frequency alternating magnetic.
Theoretical calculations considering the magnetic and viscous torques showed that the nanowires
vibrate as a consequence of the applied magnetic field. This, alongside the fact that no temperature
increase was measured during the treatment, makes the magnetomechanical effect the most probable
action mechanism in the applied treatment that is inducing cell death.
Inducing cancer cell death via magnetomechanical action using magnetic nanowires resulted in
killing up to 60% of cancer cells with only 10 minutes of treatment. The required magnetic field for
treatment is in a low power regime, which is safe, does not cause any discomfort to the patients,
and can be generated with compact and cheap instruments.
|Date of Award||Dec 2015|
- Biological, Environmental Science and Engineering
|Supervisor||Timothy Ravasi (Supervisor)|
- Magnetic nanowires
- Low-power magnetic field