Electricity controls biomolecules

Several groups of researchers are working to control kinesin and microtubules, a pair of proteins that in biological cells form a train-and-track structure for structural support, transportation and communications.

Researchers from Delft University of Technology in the Netherlands and the Max Planck Institute of Molecular Cell Biology and Genetics in Germany have found a way to use electricity to control the way microtubules connect with kinesin-coated structures.

In cells, kinesin transports cargo by walking along long, stiff microtubule filaments. The Delft and Max Planck researchers' control mechanism inverts the relationship of the proteins. They attached kinesin molecules to microfabricated gold surfaces and coaxed the molecules to propel microtubule filaments over the surfaces. The microtubules moved over distances of 2 to 10 microns. A micron is one thousandth of a millimeter.

The researchers flowed microtubules in fluid over the gold surfaces; when they applied an electric field to the gold surfaces, the negatively charged microtubules were drawn to their kinesin molecule docks. When they turned the electric field off, the microtubules detached from the kinesin and floated off the surface.

It should be possible to build nanoscale electrodes that precisely control the movements of the microtubules, according to the researchers.

The researchers are aiming to use the proteins to perform technological tasks on the nanoscale. In theory, these types of devices could give researchers precise control over matter at the molecular scale, and many individual devices could be used in parallel.

The researchers are working on ways to load cargo on individual shuttles and to actively steer and direct individual microtubules.

The work appeared in the January 8, 2005 issue of Nano Letters.