Artificial Mitotic Spindle
We are developing microscale engineering tools to investigate fundamental questions in cell biology. We found that by depositing chrome electrodes on glass and quartz substrates and applying MHz AC electric fields between them that microtubules were attracted to the electrode tips and aligned in opposed asters. The forces underlying this organization are a combination of dielectrophoretic forces and electrokinetic fluid flows, which we have investigated and modeled (1). Importantly, these microtubules can be immobilized in a geometry resembling the mitotic spindle of dividing cells. By using segmented microtubules that are biotinylated on one end, the microtubule polarity can be controlled, and we are developing this system as an experimental platform to study motor transport and microtubule bundling behavior in complex geometries such as found in cells (2).
Organizing Microtubules in vitro: Spindle-like accumulation of microtubules generated by AC voltages across micropatterned electrodes. For comparison, a static immunofluorescence image of a dividing cell at metaphase, adapted from Wittman et al (Nature Cell Biology 2001).
1. Uppalapati, M., Huang, Y.M., Jackson, T.N., and Hancock, W.O. (2008). Microtubule alignment and manipulation using AC electrokinetics. Small 4(9), 1371-1381.
2. Uppalapati, M., Huang, Y.M., Aravamuthan, V., Jackson, T.N., and Hancock, W.O. (2011). "Artificial mitotic spindle" generated by dielectrophoresis and protein micropatterning supports bidirectional transport of kinesin-coated beads. Integrative Biology (Camb) 3, 57-64.