A polarized microtubule array for kinesin-powered-nanoscale assembly and force generation

Kinesins are biological motors that transport cargo unidirectionally along microtubule tracks. These motors are attractive candidates for carrying out biomolecular separations, directed assembly of nanoparticles, or for powering nano- or microscale devices. However, a prerequisite for harnessing kinesins is properly aligning the microtubule tracks that they walk along. We describe a method for constructing an array of aligned microtubules on a two-dimensional surface. The process involves immobilizing short microtubule seeds, polymerizing long microtubules uniquely from one end, and then attaching the elongated filaments to the surface. To quantitate the extent of microtubule alignment, we analyzed microtubule orientations from four different arrays and found a standard deviation of 12.8degrees, which is comparable to the alignment of oriented microtubule arrays observed in migrating fibroblasts. By producing a field of aligned microtubules, this array provides a launching point for employing kinesins for directed assembly or nanoscale force generation.