Brownian dynamics-based estimates of polymer tension are compared with optical traps’ direct force measurements. We suspended phalloidin-stabilized, actin filaments between two beads. The positions of the beads were controlled with optical traps facilitating direct measurement of the forces acting on the beads. The lateral, thermal fluctuations of each filament were visualized with a video came...

Electrokinetics promises to be the microfluidic technique of choice for portable diagnostic chips and for nanofluidic molecular detectors. However, despite two centuries of research, our understanding of ion transport and electro-osmotic flow in and near nanoporous membranes, whose pores are natural nanochannels, remains woefully inadequate. This short exposition reviews the various ion-flux an...

The classical theory of electrokinetic phenomena assumes a dilute solution of point-like ions in chemical equilibrium with a surface whose doublelayer voltage is of order the thermal voltage, kBT/e = 25 mV. In nonlinear ‘induced-charge’ electrokinetic phenomena, such as ac electro-osmosis, several volts ≈100kBT/e are applied to the double layer, and the theory breaks down and cannot explain man...

We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro...