Devices and methods are provided for the controlled release or exposure of reservoir contents. The device includes a substrate, a plurality of reservoirs in the substrate, reservoir contents disposed in the reservoirs, discrete reservoir caps covering each reservoir to seal the reservoir contents in the reservoirs, and control circuitry for selectively disintegrating the reservoir caps to release or expose the reservoir contents in vivo. At least one of the reservoir caps comprises a first electrically conductive layer coated with one or more protective layers. In one embodiment, the control circuitry comprises an electrical input lead and an electrical output lead connected to and directly contacting each of said reservoir caps and a source of electric power for applying an electrical current through each reservoir cap in an amount effective to rupture each of the reservoir caps.