On Guard

Like many scientists and engineers, Michael Cima was inspired by the space program, and especially that inaugural lunar landing.

“I got to watch Neil Armstrong’s first step on the moon,” he notes. “I was in grammar school, and it happened pretty late at night. But I was visiting my grandparents, and they let me stay up.”

Though deeply impressed, Cima says he didn’t immediately decide he wanted to be an astronaut. Instead, he drew a broader lesson: “I was convinced that if you have a big problem, and are willing to work hard on it, you can solve it,” says Cima, now a professor of materials science and engineering at MIT.

Perhaps not coincidentally, Cima’s now helping address one of the biggest problems he’s confronted yet: the human toll taken by cancer. His invention is a device that works within the body and can give doctors key information about a patient’s health. If it proves out — and the scientist is reasonably sure it will — the technology promises not only to shed vital light on tumors but also to extend and even save lives.

INSIDER STATUS

The specific cancer problem Cima and his co-workers have targeted reflects the fact that the disease is often hidden away with the body, giving doctors limited options for monitoring it. Say someone has an inoperable tumor. This typically leaves chemotherapy and/or radiation as treatment options. But right now, the only way the doctor can tell how the regimen’s working, says Cima, “is to look at the size of the tumor.”

That can be frustrating, mainly because the tumor’s size has to change enough so conventional tests can pick up the difference. Cima’s approach is to implant a tiny sentinel that can transmit reports on a tumor’s status even if the change has been minimal. It can also give doctors important insights about whether their treatment approach is working as hoped.

The system, says the scientist, “looks like a little piece of thread.” But within a slightly porous outer shell, which would be made of either a benign polymer or silicon, it harbors a sophisticated monitoring system.

The system’s core components are nano-scale bits of highly magnetized iron oxide chemically tied to natural agents called antibodies. The latter are, in effect, connection-making machines. You can choose ones that will link up with almost any imaginable target, including specific types of cancer drugs.

Back to that patient who’s on chemotherapy: if your monitor has the right antibody, it will link up with a drug that has entered the device through the tiny openings in its outer shell. That coming together will in turn cause the iron-antibody particles, like children caught outside in a bad storm, to cling together. “When they coagulate like that,” says Cima, “you can pick it up on an MRI scanner.”

OTHER APPLICATIONS

The system could tell the doctor not only whether the drug was where it should be but also what its levels are. In addition, the device could be configured so as to pick up chemical clues that tumor cells are dying off. “That would be more useful than just knowing the drug concentrations,” notes Cima.

Another of the system’s uses would be checking for certain substances — say, hormones — that are biological markers for selected cancers. Cima and his co-workers, in fact, are right now testing to see whether their sentinels can detect a hormone, hCG, that’s a well-known sign of prostate or ovarian cancer.

The system is designed to turn up almost unimaginably small concentrations of things, whether drugs or otherwise. That could be invaluable for doctors seeking early signs, say, that a tumor has returned. “The concentrations of cancer cells in the blood can be very low,” notes Cima, “but the sad fact is that even if you have just a few such cells, it can still mean that you have cancer.”

The faculty member hopes the system will be ready to be licensed for commercial use within a year or so. Cima’s looking forward to that. Though he didn’t start out his career with the notion of confronting cancer, he’s recently had firsthand exposure to what the disease can do.

“My father-in-law died of cancer last year,” he notes. “It happened very fast, which was quite difficult.” In short, cancer is no longer an abstraction for him — and the need for new technologies to combat it is just that much clearer.

by Richard Anthony

On Topic: cancer research