How New MRI-Inspired "Smart Pills" Could Optimize Diagnostic Testing

Caltech researchers continue to refine the microscopic device, whose potential continues to grow.

It could be the next big step for diagnoses. Researchers at California Institute of Technology’s Division of Chemistry and Chemical Engineering department have worked to integrate magnetic resonance technology into microscale smart pill devices, according to a study published in Nature Biomedical Engineering.

“We said, ‘Let’s take the principles of [magnetic resonance imaging] but instead of building a MRI machine, we are going to create microchips that embody the principles of natural atoms (water, fat, muscle molecules), using the principle of an MRI machine that tells us where natural atoms are in the body,” says Mikhail Shapiro, PhD, assistant professor of chemical engineering at Caltech and Heritage Principal Investigator, co-author of the study.

Although the current way of taking pictures of the gastrointestinal tract is sophisticated, the new microscopic device, called Addressable Transmitters Operated as Magnetic Spin (ATOMS), could give physicians the ability to locate trouble areas more precisely—and without snapping photos. The technology could greatly improve diagnostic testing, experts say.

So, how does it work? First, consider the global positioning system (GPS) in your car. That technology helps you get to within a few centimeters of your destination, which is good enough when driving, but a few centimeters in the body could mean focusing on the wrong organ. Instead of using GPS principles, researchers used a conceptual approach, inspired by magnetic resonance technology that is widely used in hospitals.

“Our device contains a magnetic field sensor, integrated antennas, and a circuit (smaller than 1mm3) that adjusts its radio frequency signal based on the local magnetic field strength to wirelessly relay its location,” explains Manuel Monge, PhD, a lead author of the study.

As of now, patients swallow a pill that randomly travels through the gastrointestinal tract, capturing as much information as it can, Shapiro notes. But ATOMS enables many components to traverse the route, simultaneously transmitting information to the clinician. “It allows you to get a much more comprehensive view within your gut so there are many different locations you could read out at all times,” Shapiro says.

In the future, the technology could bring relief to patients and physicians by requiring fewer invasive procedures. Such a smart pill might one day detect a polyp in the colon, at least to the extent that an optical or biomedical measurement can do so, Shapiro says. But is the method strong enough to bring on a colon cancer diagnosis without a colonoscopy? He says it will take years of research before anyone can make that claim.

Even so, the team responsible for the innovation sees many potential uses.

“We believe that by integrating ATOMS technology with biological sensing and actuation techniques, we could enable future medical devices for a wide range of applications, from distributed monitoring of local biomarkers to targeted drug release and tissue imaging for disease diagnosis with high precision,” Monge notes. “For example, the device could monitor the health of a patient's gastrointestinal tract, blood, or brain, and relay that information to doctors.”

It will likely take several years before ATOMS hits the market, researchers say. “It is not measuring anything or taking pictures of anything, not releasing any drugs. So now our task is to combine this core technology with other elements we have previously developed,” Shapiro adds.

So far, the small size of the smart pill has proved challenging. For reference, the device can be located inside a mouse. To fit the necessary components in such a confined space while keeping power levels low required some hard work, Monge says.

ATOMS illustration has been resized. Courtesy of Ella Marushchenko for Caltech.