Scientists have created circuits that can dissolve after a certain period of time:
A new class of electronics can dissolve and disappear on a pre-set schedule, within a few minutes or a few years, depending on when you want them to go away. They could live in the body and deliver drugs, they could stick on the exterior of buildings or tanks, and they can become compost instead of metal scrap–in other words, they turn the common conception of electronics completely upside down.
The computerization of everything.