Microtubule polymerization in alignment by an on-chip temperature gradient platform

Abstract

We propose the utilization of a microfluidic platform, which generates a defined temperature gradient, for on-chip microtubule (MT) polymerization. The temperature gradient allows the MTs to be asymmetrically polymerized in a spatially-restricted, nature-mimicking environment. MTs are unidirectionally assembled and neatly aligned along the temperature gradient direction. To quantify the MT alignment, a structure-tensor-based image processing technique is employed. At the similar temperature, the MTs show an alignment within 30° under the temperature gradient field, whereas they are widely dispersed under the uniform temperature field. Further, the MT polymerization and alignments at two different tubulin concentrations are examined. The MTs polymerized at the higher concentration are aligned for a longer distance than the ones at the lower concentration due to sufficient tubulin concentration.