Implantable electrically conductive devices are provided having a nanocomposite material coating comprising gold nanoparticles or carbon nanotubes. Such an implantable device may be a neural or other implantable prosthesis, including microelectrodes for use in vivo. The devices may have dimensions on a cellular scale. Further, the devices may be highly flexible and electrically conductive, while also having low impedance and high storage charge capacity. Layer-by-layer methods for fabricating such nanocomposite materials for implantable devices are also provided. Methods for direct-write lithography patterning of such nanocomposite material coatings are also provided.