This invention describes a hermetically sealed package which can be implanted in the body. The package comprise of stacked substrates where surface of one substrate hosts biosensors which are exposed to body fluids to monitor concentrations of substances selected from analytes, metabolites, and proteins, and body physiological parameters. The structure protects from body fluids devices that interface with the biosensor electrodes for electronic data processing, powering, and wireless communication. Biosensor electrodes are electrically connected to various electronic, optoelectronic, MEM devices using novel partial silicon vias (PSVs) that prevents leakage of body fluids. Various devices are located on different substrates which are stacked to save surface area. One of the substrate forms the cover plate which permits light for powering as well as sending receiving coded data including the analyte levels.