CONTROLLING FLUID FLOW THROUGH AN ASSAY DEVICE

An assay device includes: a liquid sample zone; a reagent zone downstream and in fluid communication with the sample zone containing a reagent material; a detection zone in fluid communication with the reagent zone. The detection zone includes a substrate and a first set of projections which extend substantially vertically from the substrate. The projections have a height, cross-section and a distance between one another that defines a capillary space between the projections capable of generating capillary flow parallel to the substrate surface. The device further includes a wicking zone in fluid communication with the detection zone having a capacity to receive liquid sample flowing from the detection zone. The wicking zone includes a substrate and a second set of projections which extend substantially vertically from the substrate, and the projections have a height, cross-section and a distance between one another that defines a capillary space between the projections capable of generating capillary flow parallel to the substrate surface. The wicking zone is rectangular in shape and the longer side of the rectangle extends in the direction of flow to thereby reduce the pressure gradient in the assay device which increases the total flow time of liquid sample compared to a wicking zone having equal length sides and same volume. At least a portion of the second set of projections have at least one dimension selected from a diameter, a center-to-center spacing, or a gap between projections that is different from the first set of projections, and is selected to increase the total flow time of the sample through the device. Un dispositif de dosage comprend : une zone déchantillon liquide, une zone de réactif en aval et en communication fluide avec la zone déchantillon; une zone de détection en communication fluide avec la zone de réactif. La zone de détection comprend un substrat et un premier ensemble de saillies sétendant de manière essentiellement verticale à partir du substrat. Les saillies ont une hauteur, une section transversale et une distance entre chacune delles qui définit un espace capillaire entre les saillies, lespace étant capable de produire un flux capillaire parallèle à la surface du substrat. Le dispositif comprend aussi une zone à effet de mèche en communication fluide avec la zone de détection ayant une capacité de recevoir léchantillon liquide sécoulant de la zone de détection. La zone à effet de mèche comprend un substrat et un deuxième