Most patients with ovarian cancer are diagnosed late, after tumor cells have already infiltrated the abdominal cavity and seeded multiple tumors on multiple organs – liver, spleen, intestines, and stomach. During the clinical portion of his MD/PhD program at Harvard Medical School, Alex Bagley saw that this cancer could benefit from a blend of his two interests, biology and engineering, and he saw the Koch Institute laboratory of Sangeeta Bhatia, MD, PhD, as a good place to blend them for his PhD research. Among Bhatia's many projects, she designs multifunctional nanoparticles that can zoom to a tumor, detect changes in and around it, and improve the delivery of a therapeutic "payload."
Bagley began working with gold nanorods, tiny particles that convert the energy from near-infrared light to heat. Delivering the golden nuggets to tumors and then exposing the tumors to that wavelength causes localized heating precisely at the disease sites. Lower levels of light cause blood vessels feeding the tumor to become more porous. That allows more drugs to enter the tumor, which enhances the therapeutic impact. Higher levels of light can directly kill tumor cells.
Conveniently, the vessels feeding tumors are more porous than normal blood vessels to begin with, while the tumor's lymphatic drainage is blocked. In other words, the entrance is wide open but the exit is blocked. So when the nanoparticles are injected systemically, they naturally accumulate in tumors.
"Brilliant!" thought Bagley. "But how do we get the light into the deep abdominal cavity so that we can apply this technology to ovarian cancer?"
Posted September 13, 2012