Fluidic Indicator Device

Abstract

Disclosed is a fluidic assay device for assaying at least one property of a liquid sample, the device comprising: (i) a liquid sample application region; (ii) at least one test flow path in liquid flow communication with the sample application region; (iii) a reference flow path in liquid flow communication with the sample application region; and (iv) a junction region, at which the test flow path and the reference flow path contact one another, the junction region typically comprising an outlet, conduit, chamber or other portion which permits the onward flow of liquid; wherein a liquid flowing along the reference flow path, upon reaching the junction region, has the effect of preventing the flow of liquid along the test flow path. The invention relates to a fluidic device for the passage of a liquid. It also relates to an assay device suitable for measurement of the amount and/or presence of an analyte in, or property of, a fluid sample.

1 . A fluidic assay device for assaying at least one property of a liquid sample, the device comprising: 
 (i) a liquid sample application region;    (ii) at least one test flow path in liquid flow communication with the sample application region;    (iii) a reference flow path in liquid flow communication with the sample application region; and    (iv) a junction region, at which the test flow path and the reference flow path contact one another, the junction region typically comprising an outlet, conduit, chamber or other portion which permits the onward flow of liquid;    wherein a liquid flowing along the reference flow path, upon reaching the junction region, has the effect of preventing the flow of liquid along the test flow path.    
     
     
         2 . An assay device according to  claim 1 , wherein the test and/or reference flow paths comprise a microfluidic channel, a porous carrier, or a combination of both.  
     
     
         3 . An assay device according to  claim 2 , wherein the microfluidic channel comprises at least a portion which is of a capillary dimension.  
     
     
         4 . An assay device according to any one of claims  1 ,  2  or  3 , wherein the test and/or reference flow paths comprise one or more of the following: a filter; an incubation region; a chamber; a flow restriction.  
     
     
         5 . An assay device according to any one of the preceding claims, wherein the test and/or reference flow paths comprise a label or indicator.  
     
     
         6 . An assay device according to  claim 5 , wherein the label or indicator is mobilisable upon contact with the liquid sample.  
     
     
         7 . An assay device according to  claim 5  or  6 , wherein the label or indicator is selected from the group consisting of: an enzyme; a fluorescent dye, a colored dye; and a particle of colloidal gold or other metal.  
     
     
         8 . An assay device according to any one of the preceding claims, wherein the assay device comprises a reagent which reacts with, or a binding partner which binds to, an analyte of interest present in the sample.  
     
     
         9 . An assay device according to  claim 8 , wherein the reagent or binding partner is located in the test flow path.  
     
     
         10 . An assay device according to  claim 8  or  9 , wherein the binding partner comprises an antibody, an antigen-binding fragment of an antibody, or a multimer of an antibody or an antigen-binding fragment thereof.  
     
     
         11 . An assay device according to any one of claims  8 ,  9  or  10 , wherein the reagent or binding partner is particulate or associated with a particle.  
     
     
         12 . An assay device according to any one of claims  8 - 11 , wherein the reagent or binding partner causes agglutination in the presence of the analyte of interest, sufficient to impede or retard the flow of sample liquid along the test flow path.  
     
     
         13 . An assay device according to any one of the preceding claims, further comprising an indicator region which indicates the result of the assay.  
     
     
         14 . An assay device according to  claim 13 , wherein the indicator region is provided downstream of the junction region.  
     
     
         15 . An assay device according to  claim 13 , wherein an indicator region is provided upstream of the junction region.  
     
     
         16 . An assay device according to  claim 15 , wherein an indicator region is provided in both the test and the reference flow paths.  
     
     
         17 . An assay device according to any one of the preceding claims, wherein one or more vents are provided downstream of the junction region, whereby displacement of air or other fluid through the vents is necessary to allow liquid to advance along the test and reference flow paths.  
     
     
         18 . An assay device according to any one of the preceding claims, which provides a binary outcome for the assay result.  
     
     
         19 . An assay device according to any one of the preceding claims, which is a pregnancy-testing device and the analyte of interest comprises hCG.  
     
     
         20 . An assay device substantially as hereinbefore described and as illustrated in the accompanying drawings.  
     
     
         21 . A method of detecting the presence and/or amount of an analyte of interest in a liquid sample, the method comprising the steps of: applying the liquid sample to the sample application region of an assay device in accordance with any one of the preceding claims; and noting or recording the assay result.