Single-Molecule Observation of Anomalous Electrohydrodynamic Orientation of Microtubules

We use fluorescence microscopy to measure the orientation and shape of microtubules—which serve as a model system for semiflexible rods—that are electrophoretically driven. Surprisingly, a bimodal orientation distribution is observed, with microtubules in either parallel or perpendicular orientations to the electric field. The occupancy of these...