imaging science

Magnetism puts nanoparticles on the move

nanoparticles_1

A new imaging technology uses magnetism to noninvasively move nanoparticles inside the body. “What is novel about this whole approach and this work is that we’re using external magnetic forces to move nanoparticles within tissue, to modulate them,” Stephen Boppart explains. “Most other particles will localize somewhere and typically sit there,” he adds. “No other particle is dynamic like this, which is a unique way to generate contrast.” (Credit: Stephen Boppart, Alex Jerez, Zach Johnson/U. Illinois)

U. ILLINOIS (US)—Scientists have developed an imaging technology that uses magnetism to noninvasively move nanoparticles inside the body in order to specifically target tumor cells and other tissue.

The contrast agent technology enables micron-scale tissue detection and manipulation, and could offer a new therapeutic tool in molecular imaging, researchers say. By turning up the frequency of the magnetic field, the nanoparticles move so quickly they begin to heat up, providing a possible treatment tool.

“So now we have a platform where we can target these to a tumor, find them with contrast, measure the mechanical properties, and treat it right there,” says Stephen Boppart, a researcher at the Beckman Institute at the University of Illinois.

The development of these contrast agents for imaging is an important step in biomedical research because the technology demonstrated site-specific molecular imaging that isn’t possible with other contrast agents.

Details of the research were published online April 19 in the Proceedings of the National Academy of Sciences.

“What is novel about this whole approach and this work is that we’re using external magnetic forces to move nanoparticles within tissue, to modulate them,” Boppart explains.

“Most other particles will localize somewhere and typically sit there. They may provide a signal change, but they don’t physically move. No other particle is dynamic like this, which is a unique way to generate contrast.”

The paper reports on the method’s use in imaging mammary tumor tissue but Boppart stresses  the technology has many potential applications.

“This represents an entirely new class of imaging agents that we can use to tell more about the tissue, for diagnostic purposes and for therapeutic techniques,” Boppart says.

The magnetic nanoparticles can be used with magnetic resonance imaging (MRI) as well as optical coherence tomography (OCT) and, potentially, other imaging technologies, enabling biomechanical tissue measurements, contrast, and therapy through hyperthermia.

The technique uses magnetic forces to move nanoparticles bound to proteins, cells, tissue; phase-sensitive OCT then measures changes in light scattering from the movement. The method’s uniqueness comes from the ability to target the nanoparticles to a specific site, such as a tumor, where their multifunctionality can then be utilized.

The nanoparticles can provide information on contrast (especially valuable when it comes, for example, to distinguishing between healthy cells and cancerous cells) due to the fact that the MNPs are magnetic while the rest of the tissue is not.

Another use is to record biomechanical tissue measurements (such as cell elasticity and viscosity, important factors in disease detection). It works by using a magnetic field to make the nanoparticles vibrate, thereby providing signals from the tissue through the rate and frequency of the movements.

More University of Illinois news: www.beckman.illinois.edu/

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