"Architextured" fluid management of biological liquids

Novel "architextured" liquid-spreading and capillary flow systems are described as an adjunct to diagnostic procedures that range from the fully automated to techniques requiring no instrumentation. These systems were developed because of the observation that local features of macroscopic surfaces--roughness and chemical heterogeneity--influence both the spreading rate and equilibrium shape of liquid drops on solid surfaces. By use of organized patterns of surface structure complemented by surface chemical modification, this uncontrolled and undirected capillary flow is recast into flow behavior that is remarkably reproducible. Flow fronts are engineered to have prescribed shapes, and flow rates that are insensitive to the rheological properties of the biological liquids are obtained. To demonstrate the utility of fluid-management principles, we describe the implementation of architextured capillary configurations in microvolume liquid dispensers and potentiometric analytical systems.