Device and method for detection of analytes

Abstract

The present invention provides assays and devices for detection of substances in liquid samples. The assays and devices utilize passive diffusion between a porous material and a porous membrane containing a specific binding pair member to enable detection of the substance of interest.

What is claimed is: 
     
         1 . A device for detecting the presence or amount of a substance of interest in a liquid sample, the device comprising:
 a sample receiving zone for receiving a liquid sample,   a sample filtering zone for filtering the liquid sample, wherein the sample receiving zone and the sample filtering zone are integral with a first element;   a second element including one or more specific binding pair members at a detection zone, the one or more specific binding pair members comprising a binding pair member for  C. difficile  glutamate dehydrogenase (GDH) that specifically binds to  C. difficile  GDH,   wherein the first and second elements are separate elements,   wherein at least a portion of the liquid sample received in the sample receiving zone is permitted to move in a substantially random, non-directional manner in an area comprising at least a portion of the detection zone.   
     
     
         2 . The device of  claim 1 , wherein the one or more specific binding pair members further comprise a specific binding pair member for  C. difficile  toxin A that specifically binds to  C. difficile  toxin A. 
     
     
         3 . The device of  claim 2 , wherein the one or more specific binding pair members further comprise a specific binding pair member for  C. difficile  toxin B that specifically binds to  C. difficile  toxin B. 
     
     
         4 . The device of  claim 3 , wherein the first and second elements are in physical contact with one another. 
     
     
         5 . The device of  claim 4 , wherein the first element comprises a porous material. 
     
     
         6 . The device of  claim 5 , wherein the second element comprises a porous membrane. 
     
     
         7 . The device of  claim 1 , wherein the specific binding pair member for  C. difficile  GDH is an antibody. 
     
     
         8 . The device of  claim 2 , wherein the specific binding pair member for  C. difficile  toxin A is an antibody. 
     
     
         9 . The device of  claim 3 , wherein the specific binding pair member for  C. difficile  toxin B is an antibody. 
     
     
         10 . The device of  claim 1 , wherein the detection zone of the second element is positioned on top of at least a portion of the first element. 
     
     
         11 . The device of  claim 1 , wherein the liquid sample comprises fecal matter. 
     
     
         12 . A device for detecting the presence or amount of a substance of interest in a liquid sample, the device comprising:
 a porous material that comprises: 1) a sample receiving zone for receiving a liquid sample; and 2) a sample filtering zone for filtering at least a portion of the liquid sample received at the sample receiving zone, wherein the sample receiving zone and the sample filtering zone are integral with the porous material; and   a porous membrane that is a separate element than the porous material, the porous membrane comprising one or more specific binding pair members immobilized to at least a portion of the porous membrane, wherein the one or more specific binding pair members comprise: 1) a specific binding pair member for  C. difficile  glutamate dehydrogenase (GDH) that specifically binds to  C. difficile  GDH; 2) a specific binding pair member for  C. difficile  toxin A that specifically binds to  C. difficile  toxin A; and a specific binding pair member for  C. difficile  toxin B that specifically binds to  C. difficile  toxin B,   wherein at least a portion of the liquid sample received in the sample receiving zone is permitted to move in a substantially random, non-directional manner in an area comprising at least a portion of the detection zone.   
     
     
         13 . The device of  claim 12 , wherein the porous material and the porous membrane are in physical contact with one another. 
     
     
         14 . The device of  claim 13 , wherein the porous material and the porous membrane are in physical contact with one another in an area comprising the detection zone. 
     
     
         15 . The device of  claim 14 , wherein the porous membrane is at least partly on top of the porous membrane over the area comprising the detection zone. 
     
     
         16 . The device of  claim 12 , wherein the specific binding pair member for  C. difficile  GDH is an antibody, wherein the specific binding pair member for  C. difficile  toxin A is an antibody, and wherein the specific binding pair member for  C. difficile  toxin B is an antibody. 
     
     
         17 . The device of  claim 12 , wherein the liquid sample comprises fecal matter.