Controlling Fluid Flow Through An Assay Device

Abstract

An assay device includes: a detection zone which includes a first set of projections which are capable of generating capillary flow. A wicking zone (WZ) has a capacity to receive liquid sample flowing from the detection zone and includes a second set of projections which are capable of generating capillary flow. The WZ 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 WZ 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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This patent application claims priority to U.S. Provisional Application No. 61 / 588,772, filed Jan. 20, 2012, the disclosure of which is incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to the field of diagnostic assays, and in particular to lateral flow assays where an analyte to be detected is present in a biological or non-biological sample.BACKGROUND[0003]Diagnostic assays are widespread and central for the diagnosis, treatment and management of many diseases. Different types of diagnostic assays have been developed over the years in order to simplify the detection of various analytes in clinical samples such as blood, serum, plasma, urine, saliva, tissue biopsies, stool, sputum, skin or throat swabs and tissue samples or processed tissue samples. These assays are frequently expected to give a fast and reliable result, while being easy to use and inexpensive to manufacture. Understanda...

AI Technical Summary

Benefits of technology

The invention is directed to an assay device that includes a detection zone and a wicking zone to receive liquid samples. The wicking zone has projections that create a capillary space for the fluid to flow through and absorb reagent material. The design of the wicking zone reduces pressure gradients and increases the flow time of the liquid sample through the device. The total flow time is determined by the capillary space and the distance between the projections in the wicking zone. Additionally, the patent describes the use of circular and square shaped wicking zones to further reduce pressure gradients and decrease the flow time of the liquid sample.

Problems solved by technology

Understandably it is difficult to meet all these requirements in one and the same assay.

In practice, many assays are limited by their speed.

However, it has been found that reducing the sample size and dimensions of the device provides inadequate conjugate in the detection zone and accordingly less signal that can be read by the instrument, in some instances up to a 5× lower signal and poor sensitivity.

The inadequate conjugate in the detection zone is believed to be due to reduced sample size and inefficient use of the sample in the device, amongst other conditions.

Another drawback of reducing dimensions is the width of the detection zone will also be reduced, again making less signal available that can be read by the instrument.

Images