MIT’s Sangeeta Bhatia draws on her engineering and medical training to develop high-tech tools for tackling cancer.

Eric Smalley

A potent mix of world-class universities, research hospitals, and technology companies has made Boston a center of gravity for biotechnology. Now the same mix is nurturing a fast-emerging offshoot—nanobiotechnology.

MIT’s Sangeeta Bhatia is a 38-year-old biomedical engineer and physician who runs a multidisciplinary laboratory focused on applying nanotechnology to medicine. She is a principal investigator at the MIT-Harvard Center of Cancer Nanotechnology Excellence, one of 12 such centers across the United States funded by the National Institutes of Health.

She moved to Boston last year after six years at the University of California, San Diego because of the opportunities for collaboration and interdisciplinary work. Boston has great research facilities as well as talent, says Bhatia. “Virtually every instrument you could want, someone in town has.”

Bhatia’s lab crafts nanoparticles that deliver drugs and imaging substances to cancer tumors. The goal is to more specifically target, say, drugs to tumors and avoid the side effects common in current cancer treatment. The big challenge in using nanoscale particles as delivery agents is figuring out how to get the nanoparticles to go where you want them to go and to carry what you want them to carry.

At UC San Diego, Bhatia, along with collaborator Erkki Ruoslahti of the Burnham Institute, showed that attaching tumor-specific peptides to nanoparticles is an effective way of targeting the nanoparticles to tumors.

Bhatia has now turned her attention to the nanoparticles’ cargo—substances that, when delivered to a tumor, can slow its growth or even kill it without harming other tissue. One promising possibility is siRNA, short fragments of double-stranded RNA that block the expression of specific genes. The RNA fragments could disrupt cancer cells by blocking the cells’ production of certain key proteins. Bhatia’s lab is testing the siRNA-loaded nanoparticles in cell culture model systems and has started experiments in animals testing particular features of the technology, like targeting.

Another problem is getting enough nanoparticles to the targeted tumor. “One of the challenges of nanotechnology is that when you shrink the size of the payload down, you’re reducing the amount of drug that you can deliver,” says Bhatia.

So her team is working out ways to get nanoparticles to accumulate at tumor sites. One approach is to mimic the biology of blood clotting.

The key players in the process of clotting are platelets. They circulate in blood at a high concentration in a latent form, and when they find an injured blood vessel, they bind to it, then activate and recruit more platelets in a positive-feedback mechanism. “We’ve been trying to build that sort of functionality into our particles so that once a few of them bind to a tumor, they recruit more,” she says. Her and other labs are now testing this platelet-like accumulation of nanoparticles in animals.

Bhatia’s work bridges biology, chemistry, optics, and engineering, says Peixuan Guo, a professor of molecular virology and biomedical engineering at Purdue University in Indiana and the director of the Purdue Bionanotechnology Interdisciplinary Graduate Program. “The crossing of several fields is not easy, but a multidisciplinary background is essential for a scientist to make significant progress in bionanotechnology,” he says.

Indeed, Bhatia brings a variety of expertise into her lab. “I have chemists and engineers and biologists working side by side,” she says. “The challenge, of course, is staying up to date in all fields simultaneously, because everything is moving very fast. Because of that, we still do a lot of collaboration.”

The opportunities for collaboration in the Boston area are growing, particularly with the large presence of industry here, says Bhatia. Since the 1990s, when Bhatia did her graduate studies at MIT and Harvard, the city’s biotech

industry has greatly expanded greatly. “Cambridge doesn’t even look the same as when I left. It’s really exploded, which is very exciting.”