Nanoscale Assembly of Gold Nanowires Templated by Microtubules

There is increasing interest in using biostructures as templates to construct nanoscale-architectures. Many biosystems can self-assemble into regular structures of less than 100 nm and contain functional groups that bind to inorganic particles. In this study, fabrication of microtubule (MT)-based Au nanowires is investigated. Microtubules are fibrous proteins that are rigid hollow tubes about 25 nm in outer diameter and microns in length. We deposit nanoparticles of Au on microtubules by a new method involving photochemical reduction, in which MTs are mixed with Au3+ and the surfactant poly(oxyethelene) isooctylphenyl ether (Triton X-100 or TX-100). Exposure of the solution to UV irradiation reduces Au3+ to Au0. By varying the Au3+ and TX-100 concentration in the solution, Au particle size can be well controlled and uniform Au coverage on microtubules is observed. Multiple UV exposure steps induce Au particle growth and leads to dense coverage of Au on the MT.