A Biomimetic, Self‐Pumping Membrane

www.MaterialsViews.com C O M A Biomimetic, Self-Pumping Membrane M U N By In-Kook Jun and Henry Hess * IC A IO N Biological membranes accelerate materials exchange across the membrane by active, ATP-dependent transport via specialized channel proteins. Similarly, the integration of “pumping” driven by chemical energy harvested from the fl uid into a synthetic membrane is highly desirable from an engineering point of view, since it would obviate the need for external devices, such as pumps or centrifuges, to drive fl ow across the membrane. Here, a novel membrane integrating an electroosmotic micropump with a fuel cell is described. Electrodes deposited on the opposing surface of a membrane generate a transmembrane potential from the hydrolysis of hydrogen peroxide in aqueous solution. Short-circuiting the electrodes permits an ionic current to fl ow between the electrodes, which in turn creates a fl ow of about 1 nL cm − 2 s − 1 . Future applications of such self-pumping membranes may include implantable or remotely operating autonomous devices and membrane-based purifi cation systems. Electroosmotic micropumps are well-studied and of signifi cant promise for a wide variety of applications. [ 1–3 ] Briefl y, surface charges within a channel attract counterions which experience a force directed along the channel axis when an electric fi eld is applied across the channel. The viscous drag between counterions and fl uid in turn exerts a force on the fl uid that is localized at the channel wall, leading to a plug-like fl ow profi le. [ 4 ]