the_newsbeagle writes: Making micro-machines that work inside the body is tricky, because hard silicon and metal devices can cause problems. So bioengineers are working on soft and squishy gadgets that can be implanted and do useful work. Here's a soft biobot that's modeled on a Swiss watch mechanism called a Geneva drive. With every tick forward, the tiny gizmo releases a dose of drugs. Getting the material properties just right was a challenge. "If your material is collapsing like jello, it's hard to make robots out of it," says inventor Samuel Sia.