Magazine article Newsweek

Magnetic Bacteria Could Help Destroy Tumors and Fight Cancer; Scientists Are Testing a Way to Melt Away Cancer Using Magnetic Bacteria

Magazine article Newsweek

Magnetic Bacteria Could Help Destroy Tumors and Fight Cancer; Scientists Are Testing a Way to Melt Away Cancer Using Magnetic Bacteria

Article excerpt

Byline: Samantha Olson

Surgery. Radiotherapy. Chemotherapy.

Those are the cancer treatments most of us are familiar with, and in many cases, even all three combined are not enough to provide a complete cure. But a new and innovative approach may enable oncologists to add another option to the list. An artificial magnetic bacterium was recently created in a Spanish laboratory that, when ingested, can work as a magnetically charged compass that targets tumors and destroys them by spinning so fast the tumors heat up and melt.

It's based on an experimental treatment methodology called "magnetic hyperthermia" that exposes tumors filled with magnetic nanoparticles to an alternating magnetic field. So far, most tests have been on cancer-stricken mice.

The first step is to flood a tumor with magnetic materials, like iron nanoparticles. All of the body's cells need oxygen to function--without oxygen, a tumor couldn't grow larger than a grain of sugar, so it sends out hormone signals that allow it to hijack nearby blood vessels, which can then deliver oxygen-rich blood directly to it. However, because the blood vessels inside tumors grow in a rapid and disorganized way, they tend to be faulty and leaky.

If you inject magnetic iron nanoparticles into the bloodstream, they circulate throughout the body, bypassing the healthy blood vessels until they find entryways through the leaky ones that feed the tumor. Ultimately, iron nanoparticles will travel until they find a tumor's blood source, feed the tumor iron-laden blood and accumulate there. (It takes 24 hours for iron to fill up mice tumors; it would likely take longer to move through the human body, which has a much larger circulatory system.)

Then the patient lies in a magnetic resonance imaging (MRI) machine, where tumors can be heated up to 150 degrees Fahrenheit in just two minutes. The iron nanoparticles inside the tumor spin rapidly from the opposing magnetic poles of the MRI scan--think of what happens when you try to hold two repelling magnets next to each other. This generates heat, and once the tumor reaches temperatures of 104 degrees Fahrenheit for 60 to 90 minutes, its cells begin to break down and liquefy.

Though experiments on both lab mice and even humans in Europe have shown some successes, the challenge now is in the delivery system: Iron nanoparticle injections move throughout the body's bloodstream and become diluted, making it difficult to build up the iron levels needed to destroy the tumors.

So researchers from the University in Granada, Spain, designed digestible magnetic bacteria that could leak through the lining of the stomach in order to quickly fill local stomach tumors with iron. Patients would only have to eat yogurt or other foods laced with probiotic bacteria, and wait three hours for it to digest, to get the first step of the treatment out of the way.

Jose M. Dominguez-Vera, the lead researcher on the project, says his team has already tested the artificial bacteria in animals. The next step will be to find the right concentration of magnetic bacteria that will enable it to target tumors of the human digestive tract without harming the patient.

That's the same challenge James Hainfeld, an adjunct professor of biomedical engineering at Stony Brook University and president and chief scientist of Nanoprobes Inc., encountered. After 30 years of exploring magnetic hyperthermia, Hainfeld learned that scaling up from mice to humans is particularly difficult because of "background heating." In the human body, each molecule has its own specific absorption rate due to different degrees of magnetism, which heat up atoms to varying temperatures. …

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