A research group led by a Monash University researcher is using novel magnetic materials to help treat cancer with hyperthermia.
The use of heat to treat cancer has been around for some time, but Kiyonori Suzuki, professor and deputy head, Materials Science and Engineering at Monash University, is using well-developed materials in new ways.
Hyperthermia cancer treatment can include localised treatment on cancer cells in a small area, such as tumors, or by slightly raising part of the body’s temperature to assist with treatment such as radiation and chemotherapy.
The results have been mixed, but Suzuki’s research is hoping to change that.
Suzuki and his co-workers have been working on the research for five years, and while the material is not new, the way they are using it is a first.
Unlike conventional magnetic materials, the materials being researched exhibit a first-order magnetic transition at temperatures ideal for hyperthermia treatment.
First-order magnetic materials have traditionally been used in refrigeration as a cooling technology known as a magnetocaloric effect. One of the aims of this technology is to prevent a heat loss.
“The heat loss of this particular material has been seen as a major obstacle and we’ve never paid much attention to this side of it,” Suzuki said.
“But if you changed your standpoint and pay attention to the potential of the novel heating mechanism, the first-order materials can be seen as an ideal candidate for magnetic heating. We investigated the heating power of La-Fe-Si, a well-known first-order material, and we found that this material is an excellent candidate for hyperthermia cancer treatment.”
Suzuki’s idea came about when he was working on the heating effect of magnetic particles by applying an external magnetic field, and found the human body could only withstand very limited amounts of heat from magnetic fields.
“If you wanted to achieve a meaningful heating effect that can kill the cancer cells, you have to either apply a very large magnetic field, which would probably damage the human body itself, or a massive dosage of magnetic particles in a cancer-affected zone, which also is not realistic,” Suzuki said.
Suzuki’s team then tried using lanthanum-iron-silicon, which is a magnetocaloric material where people have previously discounted the heating effect.
“So we focused on the heating aspect of this lanthanum-iron-silicon alloy and found that it showed a heating power which is at least 10 times the heating power of the conventional materials for hyperthermia treatment,” Suzuki said.
The researchers also found the heating effect of the La-Fe-Si-H alloy is self-regulated at the Curie point, which is adjustable to therapeutic temperatures. This means the material can be heated quickly and abruptly stops heating further, which could lead to damage in healthy cells.
Suzuki said nanoparticles of the magnetic materials could be delivered to a cancer-affected zone.
“Imagine if you place a permanent magnet in a cancer-affected area from outside the body, and then the particle will be attracted to that area,” he said.
“Then after you deliver the particles to the cancer-affected zone, you can apply an external magnetic field. Now it’s an alternating current – AC. So when the AC field is applied, the magnetic particles are polarised and depolarised many times in a short period of time.
“The magnetic polarisation process is hysteretic and this hysteresis causes an energy loss. The lost energy, in the end, dissipates in the form of heat. That heat is then used to kill the cancer.”
Suzuki and his team, which includes Cordelia Selomulya at Monash University, Karl G. Sandeman at CUNY-Brooklyn College, US, and Imperial College London, UK, are still in the materials research phase and have yet to begin clinical trials. However, the researchers are now working with an oncologist from the Prince Alfred Hospital and an expert in immunology from the Faculty of Medicine at Monash University.
Suzuki is also hoping a PhD student will join the research team next year, who will be able to finish animal trials during their PhD. Further research also depends on funding.
However, Suzuki stressed that the work so far remains “proof-of-concept” where the first-order magnetic materials have been used in this manner and some factors are unknown.
“The safety of the La-Fe-Si-H alloys or the toxicity of the alloy remains unknown, so we don’t really know what’s going to happen if we put the La-Fe-Si-H in the human body,” Suzuki said.
One potential solution for avoiding toxicity is to coat the magnetic material. For example, with biosafe coating materials so the surface becomes biocompatible.
“Some elements are known to be safe. For example, iron or iron oxide or magnesium oxide. The human body already contains some of those elements,” Suzuki said.
“If we could make a first order magnetic material out of those elements that the human body contains, then it should be safer. Hence, our next target is to realise a first order magnetic material out of those biocompatible materials.”
[Image: FreeImages.com/Ana Labate]