As a graduate student at MIT, Christopher Bettinger created strong, rubbery polymers that mimic natural tissue and can be tailored to break down after anywhere from two months to two years. For Bettinger, the hardest part was making sure the molecular building blocks of his polymers were interconnected enough to yield a material that held its shape but not so strongly interconnected that the result was brittle. He initially used the new polymers to make scaffolds for laboratory-grown tissue. Now, as an assistant professor at Carnegie Mellon University, Bettinger is using them to produce degradable catheters and drug-delivery systems that he's testing in animals.

As part of his postdoctoral work at Stanford in 2009, Bettinger also created a biodegradable semiconductor for electronics used in temporary medical implants. Simple electronic circuits constructed from biodegradable materials could lead to drug-delivery devices and nerve-regeneration scaffolds that a doctor would trigger with radio frequencies from outside the body. Once therapy was complete, the devices would disappear without a trace. —Prachi Patel