A method may involve providing a conductive pattern on a bio-compatible layer. The conductive pattern may include a first conductive layer that comprises a first metal and a second conductive layer that comprises a second metal. The second conductive layer may be over the first conductive layer, and the first metal may be more malleable than the second metal. The method may also include mounting an electrical component to the conductive pattern to provide an electrochemical sensor. The electrochemical sensor may be configured for use in a body-mountable device.