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Microtubule Alignment and Manipulation Using AC Electrokinetics
Author(s) -
Uppalapati Maruti,
Huang YingMing,
Jackson Thomas N.,
Hancock William O.
Publication year - 2008
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200701088
Subject(s) - microtubule , dielectrophoresis , electrokinetic phenomena , kinesin , microelectrode , materials science , microtubule nucleation , nanotechnology , biophysics , microfluidics , electrode , chemistry , biology , microbiology and biotechnology , biochemistry , centrosome , cell cycle , cell
The kinesin‐microtubule system plays an important role in intracellular transport and is a model system for integrating biomotor‐driven transport into microengineered devices. AC electrokinetics provides a novel tool for manipulating and organizing microtubules in solution, enabling new experimental geometries for investigating and controlling the interactions of microtubules and microtubule motors in vitro. By fabricating microelectrodes on glass substrates and generating AC electric fields across solutions of microtubules in low‐ionic‐strength buffers, bundles of microtubules are collected and aligned and the electrical properties of microtubules in solution are measured. The AC electric fields result in electro‐osmotic flow, electrothermal flow, and dielectrophoresis of microtubules, which can be controlled by varying the solution conductivity, AC frequency, and electrode geometry. By mapping the solution conductivity and AC frequency over which positive dielectrophoresis occurs, the apparent conductivity of taxol‐stabilized bovine‐brain microtubules in PIPES buffer is measured to be 250 mS m −1 . By maximizing dielectrophoretic forces and minimizing electro‐osmotic and electrothermal flow, microtubules are assembled into opposed asters. These experiments demonstrate that AC electrokinetics provides a powerful new tool for kinesin‐driven transport applications and for investigating the role of microtubule motors in development and maintenance of the mitotic spindle.