Magnetic Nanoparticles For Potential Cancer Treatment

“We envision a potentialfor these materials to combine both detection and treatment into asingle process,” said Everett E. Carpenter, Ph.D., an assistantprofessor of chemistry at VCU.

Carpenter is discussing hisongoing work of the synthesis and characterization of these functionalmagnetic nanoparticles for use in biomedical applications at the 2005American Chemical Society National Meeting & Exposition inWashington, D.C., which began Aug. 28 and continues through Sept. 1.

Morethan 12,000 researchers from across the country are presenting newmultidisciplinary research and highlighting important advances inbiotechnology, nanoscience, nanotechnology, and defense and homelandsecurity.

“Eventually, our goal is to use the scientificunderstanding of the growth mechanisms of these nanoparticles todevelop materials for biomedical applications,” said Carpenter. “Byengineering the magnetic properties of enhanced ferrites it is possibleto develop materials for the treatment of various cancers, such asbreast cancer.”

Carpenter and his team are working to determinehow to best construct the core-shell structure and learn which shellmaterials are most ideal for biomedical applications such asmagnetodynamic therapy (MDT), or as MRI contrast enhancement agents.

Accordingto Carpenter, in the future it may be possible for a patient to bescreened for breast cancer using MRI techniques with engineeredenhanced ferrites as the MRI contrast agent. He said if a tumor isdetected, the doctor could then increase the power to the MRI coils andlocalized heating would destroy the tumor region without damage to thesurrounding healthy cells.

Another promising biomedicalapplication is MDT, which employs magnetic nanoparticles that arecoupled to the radio frequency of the MRI. This coupling converts theradio frequency into heat energy that kills the cancer cells. Europeanresearchers studying MDT have shown that nanoparticles are able totarget tumor cells. Carpenter said that because the nanoparticlestarget tumor cells and are substantially smaller than human cells, onlythe very few tumor cells next to the nanoparticles are killed, whichgreatly minimizes damage to healthy cells.

“Our goal is to tailorthe properties of the nanoparticles to make the use of MDT moreuniversal,” said Carpenter. “The only thing slowing down thedevelopment of enhanced ferrites for 100 megahertz applications is alack of understanding of the growth mechanisms and synthesis-propertyrelationships of these nanoparticles.

“By studying the mechanismfor the growth of the enhanced ferrites, it will be possible to createshells that help protect the metallic core from oxidation inbiologically capable media,” he said.

Enhanced ferrites are aclass of ferrites that are specially engineered to have enhancedmagnetic or electrical properties and are created through the use ofcore-shell morphology. He said that in this approach the core can be ahighly magnetic material like iron or iron alloys, while the shell canbe a mixed metal ferrite with tailored resistivity.

“Ferrites(iron oxides) are used in many applications that require both a highmagnetization and high electrical resistance; properties which aretypically mutually exclusive,” said Carpenter. “These two propertiesare tied not only to the structure of the material but also to the wayin which the material is synthesized and processed.”

Today,polymer encapsulated iron oxide particles are used in biomedicalapplications. However, Carpenter said that the high magnetization ofthe enhanced ferrite nanoparticles may potentially improve theabsorption of the radio frequency, thereby providing better detectionof tumor regions and the use of less MRI contrast re-agent.

In2002, Carpenter invented a new material based on metallic iron. He saidthe magnetic power of the iron nanoparticles he created is 10 timesgreater than that of the currently available iron oxide nanoparticles,which translates to a substantial reduction in the amount of ironneeded for imaging or therapy.

This work is supported by a grant from the American Cancer Society and the VCU Department of Chemistry.