Biological molecules like DNA can be used as components in nanometer-scale devices such as electrical nanocircuits (1-3). However, fabrication of such devices poses serious difficulties for conventional manufacturing methods. To circumvent these difficulties, we are exploring novel approaches to pattern DNA on engineered surfaces using biomolecular motors. Our experimental method is based on a gliding motility assay, where microtubules are propelled over the surface of a substrate by kinesin motor proteins. The potential to use such motile microtubules as molecular shuttles for the transport of nanocargo (such as streptavidine coated beads) has been explored recently and is reviewed in (4).
Here, we report on the feasibility to not only transport but also to mechanically manipulate nanostructures by the forces of kinesin. In particular, we demonstrate the simultaneous stretching of multiple λ-phage DNA molecules between a substrate surface and moving microtubules. For that, the DNA molecules are functionalized on one of their ends such that a strong binding to predetermined contact points (e.g. gold patterns on a glass or silicon substrate) is possible. The other end of the DNA is biotinylated, and can be readily picked up by biotinylated microtubules via a streptavidine linkage. The forces produced by such a kinesin-driven system are strong enough to stretch the DNA molecules to their full contour length of 17 µm. The motile microtubules are thus employed as forceful grippers in the nanometer range. In contrast to conventional nanomanipulation methods these grippers are small and their work can be highly parallelized. By combining this approach with previously described methods to guide the movement of microtubules along predefined tracks, we aim to construct large area networks of stretched DNA molecules as templates for subsequent metalization and use as nanoelectronic circuits.
(1) E. Braun, Y. Eichen, U. Sivan, G. Ben-Yoseph: DNA-templated assembly and electrode attachment of a conducting silver wire, Nature391, 775-778 (1998).
(2) M. Mertig, R. Seidel, L. Colombi Ciacchi, W. Pompe: Nucleation and growth of metal clusters on a DNA template, AIP Conference Proceedings633, 449-453 (2002).
(3) M. Mertig, L. Colombi Ciacchi, R. Seidel, W. Pompe, A. De Vita: DNA as a selective metallization template, NanoLetters2, 841-844 (2002).
(4) H. Hess, V. Vogel: Molecular Shuttles based on motor proteins: active transport in synthetic environments, Reviews in Molecular Biotechnology, 82, 67-85 (2001).