As consumers, we want our electronic gadgets to be durable. But as patients, we might want them to dissolve — inside our bodies. Scientists reported Thursday that they succeeded in creating tiny medical devices sealed in silk cocoons that did the work they were designed for, then dissolved in the bodies of lab mice. It's an early step in a technology that may hold promise, not only for medicine, but also for disposal of electronic waste.In the experiment, the devices were designed to generate heat, a potential strategy for fighting infection after surgery by killing germs, said John Rogers of the University of Illinois at Urbana-Champaign, an author of the study.The devices worked in the mice for more than a week, until their silk coatings dissolved enough for bodily fluids to erode key parts of the devices, he said. After three weeks, the tiny gadgets had basically disappeared.Someday, for people, similar devices might be programmed to monitor the body and release drugs accordingly, or produce electric current to accelerate bone healing, Rogers said.