Donhee Ham, 34

Combined with specially engineered magnetic nanoparticles, nuclear magnetic resonance (NMR) is a potentially fast and easy way to spot cancer, bacteria, and viruses in blood samples. But current NMR systems use large and expensive magnets, making them impractical for, say, widespread cancer screening and other routine diagnostic tests. So Donhee Ham, an associate professor of the natural sciences, built a system that is only slightly bigger than a cell phone and weighs less than two kilograms--yet is 60 times as sensitive as existing 120-kilogram tabletop systems that could cost 70 times as much. The key is a silicon radio-frequency chip that compensates for the low-quality signal caused by using a smaller magnet. The system has been tested in collaboration with Massachusetts General Hospital, and companies have expressed interest in incorporating Ham's technology into diagnostic instruments. --Brittany Sauser