By Will Soutter
Scientists from the nanotech research collaborative Nanoprobes have developed a treatment for cancer using magnetic nanoparticles, which has cured 80% of mice in initial trials.
The principle behind these amazing results is surprisingly simple - in an oscillating magnetic field, such as that used by an MRI machine, iron nanoparticles spin backwards and forwards at high speed, generating a lot of heat.
If these particles can be delivered into cancerous tumours, the heat could be used to destroy the cells without affecting the nearby healthy tissue - a process called cancer hyperthermia.
This technique has been one of the most discussed nanoparticle-based mechanisms of cancer treatment for several years.
The trick, however, is getting the iron nanoparticles into the tumours in high enough concentrations without exposing the rest of the body to toxic levels of iron.
Attempts to inject the iron directly into the tumours tended to miss some parts, and tumours that were too deep or had metastasized were very difficult to kill.
Dr James Hainfield, the senior researcher on this project, along with student Hui Huang, developed a solution to these issues.
They removed the problem of iron toxicity by wrapping the iron core of the nanoparticle in a layer of biocompatible polymer - preventing the iron from contacting the body directly without stopping it from responding to the magnetic field.
Once the iron was in the body, they still had to get as much of it as possible into the tumours themselves. To achieve this, the researcher exploited a useful property of blood vessels.
Blood vessels are quite leaky when they first grow, and gradually develop a tighter seal over time. Because tumours grow at an uncontrolled rate, they demand more blood vessels to grow faster than usual in and around them - making the blood vessels in the vicinity much more permeable than normal.
Hainfield and Huang tuned the size of their coated iron nanoparticles to be just small enough to fit through the gaps in these newly-formed blood vessels, but large enough that normal blood vessels can safely contain them.
This was shown to lead to higher concentrations of iron in the tumours - up to sixteen times higher than in the surrounding tissue.
These modifications to the technique, perfected over six years of work, have proved a resounding success.
The team can now boast proven cure rates of 78-90% in mice - the animals showing no adverse effects after the treatment, which lasts just three minutes.
The benefits of this type of treatment as opposed to surgery, chemotherapy, or radiation, are clearly huge. The ability to destroy tumours without surgery will be revolutionary in deep areas or in the brain, where surgery is impossible or at least highly invasive.
The nanoparticle therapy is also expected to work well in conjunction with more conventional treatments - vastly improving the efficacy of chemo- and radiotherapy.
The Nanoprobes team are currently sourcing funding for the clinical trials necessary to get FDA approval for the treatment. They are highly optimistic, and it is easy to see why - this marks a major milestone on the road to a cure for cancer.