Engineering devices based upon the interfacing of biological with inorganic systems have led to fascinating research results and present important implications for next-generation technologies. The development of cell- and protein-based micro/nano systems has demonstrated that several key factors must be considered when establishing fabrication rules. These include material interface properties, preserving biological viability, as well as self-assembly as a device-fabrication methodology, to name a few. Here, we present two proposed devices that have been developed through the application of these principles. They include muscle-powered microfabricated devices, as well as protein-functionalized polymeric vesicles based on protein-coupling reactions. These systems have successfully bridged the gap between biological and conventional engineering to yield exciting prospects, as well as important lessons and questions for the development of cell-/protein-based hybrids.