A new study showed that researchers developing nanoparticles that can zap tumors with significant amounts of heat under a low magnetic field. That's the promise of heated magnetic nanoparticles, a futuristic-sounding technology that could one day be used to fry and eradicate cancer cells without harming healthy tissue elsewhere in the body. The study was published online in the journal Small.
The main accomplishment of our work is the greatly enhanced heating performance of nanoparticles under low-field conditions suitable for clinical applications. The best heating power we obtained is close to the theoretical limit, greatly surpassing some of the best-performing particles that other research teams have produced.
The treatment will only heat up the region where nanoparticles are without affecting healthy tissues that are further away, so we anticipate few side effects. Also, the magnetic field that's used to excite the particles can penetrate deep into the body from an instrument that does not require any contact or insertion of probes. As such, the therapy can reach parts of the body that are not easily accessible to surgery.
A lot more research needs to be done before the nanoparticles are available to patients. But here's how the therapy would work: First, doctors would use targeting technologies to direct nanoparticles to tumors in patients' bodies.
Then, exposure to an alternating magnetic field would prompt the particles' magnetic orientation to flip back and forth hundreds of thousands of times per second. This process would cause the particles to warm up as they absorbed energy from the electromagnetic field and converted it into thermal energy in the targeted regions.
This form of cancer treatment is known as magnetic nanoparticle hyperthermia, and it's not new. Researchers designed new magnetic nanoparticles that get hotter and generate heat a few times faster than some of the highest-performing magnetic nanoparticles studied under low-field conditions.
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 manganese-cobalt-ferrite particles reached maximum heating power under high magnetic fields. But the biocompatible zinc ferrite particles heated up with impressive efficiency under an ultra-low field.
Zinc Ferrite Particles
The bottom line is our zinc ferrite particles are designed for low fields suitable for clinical applications. For other particles reported in the literature, the field used is typically higher. Most of these other particles are not capable of heating at our chosen field parameters.
Tested in magnetic bone cement
Zeng envisions bone cancer treatment as one early application for heated magnetic nanoparticles. As he explains, Typically, after a surgery to remove bone tumors, a synthetic material called bone cement is injected to fill the voids. 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 cancer.
Authors embedded their zinc ferrite nanoparticles into bone cement and used it to heat up a pork rib. With just a small number of nanoparticles (1 percent of the bone cement, by weight), the experimental set-up reached a temperature high enough to kill tumor cells.