Microtubules are excellent candidates for the fabrication of nanostructures, including nanowires. A method for controlled nucleation and growth of microtubules on substrates (e.g., gold on a silicon wafer) is provided. The substrate is functionalized with a nucleating agent for microtubule growth. The method can be employed to generate nanoscale structures on substrates or between substrates by additional attachment of MT capture agents which function to capture the ends of growing MT to form connecting MT structures. The method can be used to form 2- and 3-D structures on or between substrates and can function to establish interconnects between nanoscale devices or molecular electronic devices and electrodes. A specific method for metallization of biological macromolecules and structures in provides which can be beneficially applied to metallized the MT formed by the growth and capture method. The metallization method is biologically benign and is particularly useful for copper metallization of MTs.