Sangeeta Bhatia often finds herself the only engineer in a roomful of clinicians, or the only physician in a roomful of engineers. A biomedical engineer who is also a Harvard Medical School-educated physician, Bhatia, SM ‘93, PhD ‘97, employs microscale technology to help find novel solutions to problems in biology and medicine. Few researchers manage to bridge the gap between medicine and engineering single-handedly. Bhatia does.
“I’m a technophile, and I love a clever, elegant solution,” says Bhatia, who has a joint appointment to the Harvard-MIT Division of Health Sciences and Technology and the Department of Electrical Engineering and Computer Science. “But the other pressure in me is that I was trained as a physician to improve human health and understand human disease. I’m a scientist, too, and I want to understand a problem deeply.”
Bhatia designs artificial devices on the size scale of cells–with features measured in micrometers–that allow her to study and manipulate cell behavior more precisely than was previously possible. Her lab focuses on liver cells, probing their natural environment to better understand how they function. Her work is both fundamental and practical and combines artificial materials with living cells to help solve real problems in medicine, such as artificially engineering liver tissue and finding better ways to screen drugs for liver toxicity.
Though trained as a physician, Bhatia has chosen to devote herself full time to bioengineering research, first at the University of California, San Diego, and now at MIT, to which she returned in 2005 to lead the Laboratory for Multiscale Regenerative Technologies. Bhatia began studying the liver as a PhD student in medical engineering at HST, when she worked in the laboratory of Mehmet Toner at Massachusetts General Hospital. “Over the years, I just fell in love with this particular tissue and trying to understand it,” she says. The liver is a football-sized chemical plant responsible for several critical tasks, such as metabolism and bile secretion. With more than 17,000 people in the U.S. waiting for liver transplants, surgeons recognize that there is a critical need for alternative ways of replacing liver tissue.
Toner’s lab was working on manipulating liver cells so that they could be housed in external devices to help patients with liver failure in the same way that dialysis machines help those with kidney failure. But the cells of the liver are very difficult to keep in culture; when taken out of their native environment, they quickly cease to function. They must be grown, arranged, and kept stable on an artificial platform. “If you’re trying to make a cartridge of these cells, and they’re not working very well, then you don’t have a prayer of sustaining your patient,” says Bhatia.
Bhatia continues to hunt for better ways to culture liver cells outside of the body. She studies and manipulates cells with devices constructed on the cellular scale. The enabling technology is not new; engineers have used photolithography for decades to etch tiny patterns in surfaces when laying down circuits in computer microchips. But the same techniques have only recently been applied to biology, and Bhatia’s knowledge of both fields has put her at the forefront of their synthesis. The purpose of the tools that Bhatia develops is what she terms “deconstructing the environment around the cell.” Liver cells range in size from about 10 to 50 micrometers, and their function is largely controlled by their environment. “Ten to a hundred microns is technology that was invented in the ’80s,” Bhatia says. “But if we apply it cleverly to biology, we can control that environment, and people have not done that before.”