Various nanoparticles can be directly assembled into parallel wires, cross-wires, and many other complex structures using micro-and nanoscale templates. Non-uniform electric fields are utilized to direct the large scale assembly of colloidal nanoparticles in nanoscale structures. The assembly process is controlled by electric field, time and geometric design of templates. Single nanoparticle wires as small as 10 nm wide and 100,000 nm long as well as other nanoparticle structures can be fabricated using electrophoresis over a large area. In addition, the directed assembly of polymeric and conductive nanoparticle nanowires and networks has been shown using dielectrophoresis. The nanoparticle wires can be further oriented along the direction of an externally introduced hydrodynamic flow for large scale manufacturing of nanoscale devices suitable for many applications including biosensors and nanoelectronics.