Thiolated peptide nanotube assembly as arrays on patterned Au substrates

A variety of nanotubes were addressed to particular directions by using external forces such as microfluidics, magnetic fields, electric fields, and the Langmuir-Blodgett technique. Recently in another approach, nanotubes were assembled by chemical interactions. For example, nanotubes coated by proteins were assembled onto the complimentary ligand-patterned substrates in solution. Molecular recognitions, hydrogen bonding, hydrophobic interactions, and charge interactions were also applied to locate nanotubes in the specific regions on substrates. In this report, we assembled thiolated peptide nanotubes by using one of the stronger chemical interactions, thiol-Au interaction. Due to the strong thiol-Au interaction, the nanotubes show a strong affinity toward Au substrates and the nanotubes were only addressed to Au regions on the substrates. Because of the strong affinity, the nanotube assembly could be scaled up to form nanotube arrays by patterning Au pads on the substrates with AFM-based nanolithography. This technique may lead to an alternative nontraditional fabrication method for electric circuits because the physical properties of aligned peptide nanotubes can be tuned after the targeted positioning with semiconductor/metal coatings on the nanotubes with simple chemical procedures.