Abstract: The invention refers to a method for control of a volume flow in an osmotic micropump and an osmotic micropump. According to the invention, the osmotically driven volume flow of the solvent through the sempipermeable diaphragm of an osmotic micropump is controlled by the transfer of a solute, which is not freely permeable through the diaphragm, from a source chamber to the pump's delivery chamber. According to the invention, the delivery chamber is formed as a dilution chamber, wherein the solution is flow out along a convective dilution path close to the semipermeable diaphragm. Due to the entrance of the solvent, a stationary osmotic gradient can be achieved along the convective flow path in the dilution chamber. The invention allows the maintenance and control of the flow rate. It is able to move a volume which is large in comparison to the combined volume of the source chamber and the dilution chamber.

Abstract: The invention relates to an assay method and a fluid microsystem for carrying out said assay method, in particular, for carrying out miniaturized affinity tests in a micro-array format. According to said invention, a liquid phase comprising at least one type of detectable high-molecular weight soluble substance, for example a labeled reaction partner or product of an affinity reaction is displaced by the hydraulic effect of a high-molecular weight osmotic agent on an ultrafiltration membrane towards a miniaturized measuring chamber defined thereby. The fraction of the detectable high-molecular weight substance(s) is concentrated in the measuring chamber, while the dissolved low-molecular weight components are removed with the solvent through the membrane pores, thereby making it possible to attain a high detection sensitivity.

Abstract: The invention relates to an assay method and a fluid microsystem for carrying out said assay method, in particular, for carrying out miniaturized affinity tests in a micro-array format. According to said invention, a liquid phase comprising at least one type of detectable high-molecular weight soluble substance, for example a labeled reaction partner or product of an affinity reaction is displaced by the hydraulic effect of a high-molecular weight osmotic agent on an ultrafiltration membrane towards a miniaturized measuring chamber defined thereby. The fraction of the detectable high-molecular weight substance(s) is concentrated in the measuring chamber, while the dissolved low-molecular weight components are removed with the solvent through the membrane pores, thereby making it possible to attain a high detection sensitivity.

Abstract: The invention refers to a method for control of a volume flow in an osmotic micropump and an osmotic micropump. According to the invention, the osmotically driven volume flow of the solvent through the sempipermeable diaphragm of an osmotic micropump is controlled by the transfer of a solute, which is not freely permeable through the diaphragm, from a source chamber to the pump's delivery chamber. According to the invention, the delivery chamber is formed as a dilution chamber, wherein the solution is flow out along a convective dilution path close to the semipermeable diaphragm. Due to the entrance of the solvent, a stationary osmotic gradient can be achieved along the convective flow path in the dilution chamber. The invention allows the maintenance and control of the flow rate. It is able to move a volume which is large in comparison to the combined volume of the source chamber and the dilution chamber.