A method for controlling fluid flow in an assay device that employs a membrane is provided. Specifically, one or more recessed regions are formed in the membrane by applying a solvent treatment thereto. The solvent treatment is selected based on its particular dissolving capacity for the material used...http://www.google.de/patents/US8124421?utm_source=gb-gplus-sharePatent US8124421 - Flow control technique for assay devices
