Directing transport of CoFe₂O₄-functionalized microtubules with magnetic fields

The external magnetic fields can be used to control the transport direction of magnetically labeled microtubules driven by kinesin motors in vitro without affecting their transport speed by selectively functionalizing microtubule segments with 20-nm CoFe₂O₄ magnetic nanoparticles. Kinesin motor proteins convert chemical energy derived from the hydrolysis of adenosine triphosphate (ATP) into mechanical energy to move intracellular cargo along microtubules, cylindrical polymers of the tubulin that act as intracellular conduits. This approach provides a significant alternative to serial methods such as optical tweezers. Magnetically labeled microtubules additionally provide a new tool for in vitro investigations of the role of microtubules and motors in important cellular processes such as cell division, axonal transport, and flagellar motility.