Magnetic nanoparticles put the heat on cancer
Cancer is one of humanity's biggest killers, but scientists are coming up with some creative ways to fight back. Researchers at the University at Buffalo have developed new kinds of nanoparticles that can infiltrate, heat up and kill cancer cells more effectively and efficiently than similar methods.
Using nanoparticles to fight cancer has become a growing area of research in recent years. The general concept is to get the particles into tumors, before activating them with radiation to trigger a reaction that destroys the cancer cells without harming healthy tissue. What kind of nanoparticle and radiation are used can vary, as can the type of reaction that's triggered.
Previous work has killed tumors by activating CeF3 nanoparticles with X-rays to create toxic singlet oxygen, used infrared light to ramp up cancer's pH balance, used laser pulses to heat up gold nanoparticles, or a combination of several of these.
The new study uses a technique known as magnetic nanoparticle hyperthermia, and it works on a similar basis. Magnetic nanoparticles are introduced into tumor cells before an alternating magnetic field is applied to the area. That makes the particles flip back and forth hundreds of thousands of times per second, heating them up to the point of destroying the cancer cells.
The procedure itself isn't all that new, but the Buffalo study has boosted the effectiveness of the treatment. This is done by designing nanoparticles that react strongly to relatively low-strength magnetic fields.
"Within the body, heat energy is continuously carried away – for example, by blood flow – making it difficult to reach the required temperature to kill cancer cells," says Hao Zeng, lead researcher on the project. "One needs particles with the highest heating power possible. Our particles have demonstrated impressive heating power even at low magnetic field amplitude and frequency deemed safe for human body."
The team created two types of these nanoparticles, one made of manganese cobalt ferrite and the other of zinc ferrite. Of the two, the zinc particles fared much better, heating up efficiently even under an ultra-low magnetic field.
Magnetic nanoparticle hyperthermia is minimally invasive and should produce few harmful side effects. It also overcomes one of the major hurdles of nanoparticle treatments activated by light – namely, the magnetic field can penetrate far deeper into the body, whereas light can really only attack cancers close to the surface of the skin.
In fact, the Buffalo researchers believe that one of the first applications for the treatment could be bone cancer. The zinc ferrite nanoparticles could be embedded into bone cement, a synthetic material that's often used to plug up cavities left behind after removing bone tumors.
"If we introduce our nanoparticles into the bone cement, they can be heated on demand to kill any tumor cells that remain nearby, and help prevent recurrence of the cancer," says Zeng.
To test the idea, the team added magnetic particles to bone cement and injected that into a pork rib. Sure enough, the technique worked to heat up the bone to temperatures that could kill cancer cells.
Although the concept is promising, the team says that there's still plenty more work to be done.
The research was published in the journal Small.
Source: University at Buffalo
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