Silicon Pharmacist: A drug-delivery device under development by MicroChips Inc. is a silicon chipwith 100 or more nanoliter-size wells containing either drugs or biochemicalsensors [center]. Each well is covered by a thin metal foil, which is connectedto wires on the face of the chip. When current runs through a well's wire, themetal foil breaks open, releasing a drug or exposing a fresh biochemical sensor [right].

The chip is fastened to the outside of a pocket-watch-size electronics package that is implanted beneath the skin [left]. Within the package is an antenna that receives instructions via radio and a microprocessor that controls the opening of individual wells.