Polarized alignment and surface immobilization of microtubules for kinesin-powered nanodevices

Kinesin is a nanometer-scale, ATP-powered molecular motor protein that steps along the surface of microtubules. The microtubule tracks are cytoskeletal filaments, 24 nm in diameter, with an overall structural polarity that results from their asymmetric tubulin subunits. Kinesin recognizes the structural polarity and moves toward only one end of a microtubule. A major obstacle in the way of creating kinesin-powered devices is the development of methods for the controlled positioning and alignment of the microtubule tracks. Only by positioning microtubules with defined polarity can kinesin transport, or force generation, be directed efficiently within a device. Here, we report a method to surface immobilize microtubules with approximately 90% parallel alignment using a single-chain antibody that binds alpha-tubulin exposed at the microtubule minus end.