A mountable device includes a bio-compatible structure embedded in a polymer that defines at least one mounting surface. The bio-compatible structure includes an electronic component having electrical contacts, sensor electrodes, and electrical interconnects between the sensor electrodes and the electrical contacts. The bio-compatible structure is fabricated such that it is fully encapsulated by a bio-compatible material, except for the sensor electrodes. In the fabrication, the electronic component is positioned on a first layer of bio-compatible material and a second layer of bio-compatible material is formed over the first layer of bio-compatible material and the electronic component. The electrical contacts are exposed by removing a portion of the second layer, a conductive pattern is formed to define the sensor electrodes and electrical interconnects, and a third layer of bio-compatible material is formed over the conductive pattern. The sensor electrodes are exposed by removing a portion of the third layer.