The present disclosure describes a device and method to clear solutes from a patient's blood while maintaining fluid balance. In some implementations, the device and method is used to assist the filtration functions of a patient's liver or kidney. The device includes a plurality of hollow fibers that pass through a sequence of alternating filtration chambers and infusion chambers. The filtration chambers filter the patient's blood while the infusion chambers rehydrate the filtered blood.

A method of operating a membrane is provided. The membrane comprises: a porous layer; a first electrically conductive layer located on a first side of the porous layer; and a second electrically conductive layer located on a second side of the porous layer. When an electric voltage is applied between the first and second electrically conductive layer across the porous layer, the membrane prevents moisture intrusion from a first surface of the membrane towards a second surface of the membrane. The method comprises applying an electric voltage between the first and second electrically conductive layer across the porous layer to prevent moisture intrusion from the first surface of the membrane towards the second surface of the membrane when it is desired to prevent moisture intrusion from the first surface towards the second surface. A membrane system for performing the method is also provided.