Dielectrophoretic measurement of bacterial motor characteristics

Novel methods of the bacterial motor characteristic measurement using AC field effects in a microfabricated electrode system are presented. Two methods are developed in this paper. One is the measurement of the external force-to-velocity characteristics (F-v) of swimming bacteria. Electrostatic orientation of bacteria parallel to the field lines is used to guide the bacterial locomotion along a line. dielectrophoresis is used to apply external force both forwards or backwards to the swimming bacteria, and by measuring the velocity of the locomotion, the F-v curve is obtained. The other is the measurement of torque-to-speed characteristics (T- omega ) of the motor. Electrorotation is used to apply external torque to the tethered cells, and by changing the applied torque to the tethered cells, and by changing the applied torque and measuring the rotation speed, T- omega curves obtained.<>