Abstract: A device for isoelectric focusing. The device comprises a focusing container configured to contain an electrolyte solution and having a longitudinal axis and at least one electrolysis unit mounted in a close proximity to the longitudinal axis. Each electrolysis unit injects an ion flow into the focusing container so as to create a pH gradient having a plurality of steps in the electrolyte solution, along the longitudinal axis. Each step has a substantially uniform pH level and the pH gradient is defined by at least one pH ramp between every two sequential steps of the plurality of steps.

Abstract: A method for a tactile presentation of perceivable content. The method comprises receiving a data representing perceivable content, selecting a plurality of electric currents according to the data, each the electric current is associated with at least one of a plurality of regions of a solution having a plurality of macromolecules, and changing a level of acidity (pH) of at least one of the plurality of regions by applying a respective the electric current thereto. A proton concentration in the plurality of regions tactilely presents the perceivable content.

Abstract: A specified proton concentration in a volume (80) is produced by passing a controlled electrophoresis current through an adjacent electrophoresis volume (28) between a working electrode (26) and a counter electrode (24). An array of such volumes with specified proton concentration is used to provide the pH gradient for isoelectric focusing.

Abstract: Disclosed are methods for controlling molecular interactions where at least one member of a pair of chemical entities having a pH-dependent affinity is immobilized on the surface of an electrode. By changing the potential difference between the electrode and a counter electrode, the affinity of the pair of chemical entities is changed, changing the tendency of the pair to bind or to dissociate. Disclosed are also devices useful for implementing the methods of the present invention.