Electronics with integrated energy harvesting devices, sensors and actuators are becoming pervasive embedded systems in monitoring health, conditioning for sports, improving energy efficiency of combustion engines and improving the overall quality of life. In this talk I will discuss three examples from my research in the development and applications of microsystems in prosthesis, in engine efficiency and in sensing. These seemingly disparate applications have many important elements in common such as interfacing with harsh environments (biological as well as industrial), low power requirements, etc. I will also discuss nanotechnologies that offer some unique solutions such as type II photovoltaic cells for energy harvesting and nano-texturing for efficient electrodes-tissue interfacing. A specific example involving impedance-matched electrodes to efficiently transduce extracellular electrical activities will be discussed. These micro-machined electrode arrays on compliant silicon cantilever beams were coated with carbon nanotubes to provide a large interface with bi-lipid membranes and produced signals an order of magnitude better than the un-coated electrodes. The compliant slightly hydrophobic beams interacted with the membranes through Van der Waals forces and attached themselves to the bi-lipid membranes producing very large interfacial capacitance resulting in an excellent cell transduction.