Solid phase chromatographic immunoassay

Abstract

A chromatographic test strip comprising a solid support having at least a first portion and a second portion with said portions being in the same plane so as to permit capillary flow communication with each other. The sample is added to the first portion. The first portion also may comprise a tracer portion having a tracer movably supported therein. The tracer consists of a visible particulate marker. In the second portion, a binder is immobilized. The test strip is useful in a variety of immunoassays.

What is claimed is:  
     
       1. A test strip for determining the presence of an analyte in a liquid sample comprising a solid support, said solid support comprising at least a first portion and a second portion, said portions being in the same plane so as to permit capillary flow communication with each other; 
       said first portion being the site for application of the liquid sample and further comprising a tracer site, said tracer site consisting of a tracer movably supported therein wherein said tracer comprises a ligand, which specifically binds to the analyte, conjugated to a visible particulate marker; and  
       said second portion being the site for visually determining the presence of the visible particulate marker, said second portion consisting of a binder immobilized therein which specifically binds to the analyte.  
     
     
       2. The test strip of  claim 1  wherein the solid support comprises nitrocellulose. 
     
     
       3. The test strip of  claim 1  wherein the visible particulate marker is selected from the group consisting of colloidal metals, colored liposomes, colored polymeric beads and polymerized dye molecules. 
     
     
       4. The test strip of  claim 3  wherein the visible particulate marker is a colored liposome. 
     
     
       5. The test strip of  claim 3  wherein the visible particulate marker is a colored polymeric bead. 
     
     
       6. The test strip of  claim 1  wherein the analyte is an antigen and the ligand and the binder are antibodies thereto. 
     
     
       7. The test strip of  claim 1  wherein the ligand and the binder are antigens or analogs thereof and the analyte is an antibody thereto. 
     
     
       8. The test strip of  claim 1  wherein the first portion and the tracer portion are spatially separate from each other with the first portion being upstream of the tracer portion. 
     
     
       9. A no-wash, one-step method for determining the presence of an analyte in a liquid sample consisting of the steps of: 
       a) adding a liquid sample to the first portion of the test strip of  claim 1 ;  
       b) allowing sufficient time for the liquid sample to flow to the second portion of the test strip; and  
       c) determining the presence of the analyte in the liquid sample by visual inspection of the second portion for the visible particulate marker wherein the presence of the analyte is indicated by the presence of the visible particulate marker.  
     
     
       10. The method of  claim 9  wherein the liquid sample is added to the test strip by immersing the first portion into the liquid sample. 
     
     
       11. A test strip for determining the amount of an analyte in a liquid sample comprising a solid support, said solid support comprising at least a first portion and a second portion, said portions being in the same plane so as to permit capillary flow communication with each other; 
       said first portion being the site for application of the liquid sample and further comprising a tracer site, said tracer site consisting of a tracer movably supported therein wherein said tracer comprises a ligand, which is the analyte or an analog thereof, conjugated to a visible particulate marker; and  
       said second portion being the site for visually determining the amount of the visible particulate marker, said second portion consisting of a binder immobilized therein which specifically binds to the ligand.  
     
     
       12. The test strip of  claim 11  which consists of a third portion in the same plane as the first and the second portions, all of said portions being in capillary flow communication with each other, and said third portion being an additional site for visually determining the amount of visible particulate marker bound therein. 
     
     
       13. The test strip of  claim 11  wherein the visible particulate marker is selected from the group consisting of colloidal metals, colored liposomes, colored polymeric beads and polymerized dye molecules. 
     
     
       14. The test strip of  claim 13  wherein the visible particulate marker is a colored liposome. 
     
     
       15. The test strip of  claim 13  wherein the visible particulate marker is a colored polymeric bead. 
     
     
       16. The test strip of  claim 11  wherein the analyte is an antigen. 
     
     
       17. The test strip of  claim 11  wherein the analyte is an antibody. 
     
     
       18. The test strip of  claim 11  wherein the first portion and the tracer portion are spatially separate from each other with the first portion being upstream of the tracer portion. 
     
     
       19. A no-wash, one-step method for determining the presence of an analyte in a liquid sample consisting of the steps of: 
       a) adding a liquid sample to the first portion of the test strip of  claim 11 ;  
       b) allowing sufficient time for the liquid sample to flow to the second portion of the test strip; and  
       c) determining the presence of the analyte in the liquid sample by visual inspection of the second portion for the visible particulate marker wherein the presence of the analyte is indicated by the absence of the visible particulate marker.  
     
     
       20. A no-wash, one-step method for determining the amount of an analyte in a liquid sample consisting of the steps of: 
       a) adding a liquid sample to the first portion of the test strip of  claim 12 ;  
       b) allowing sufficient time for the liquid sample to flow to the second portion and the third portions of the test strip; and  
       c) determining the amount of the analyte present in the liquid sample by visual inspection of the second portion and the third portion for the amount of the visible particulate marker bound in each portion wherein the presence of the analyte is indicated by the absence of the visible particulate marker.  
     
     
       21. The method of  claim 19  wherein the liquid sample is added to the test strip by immersing the first portion into the liquid sample. 
     
     
       22. The method of  claim 20  wherein the liquid sample is added to the test strip by immersing the first portion into the liquid sample. 
     
     
       23. The test strip of  claim 11  wherein the solid support comprises nitrocellulose. 
     
     
       24. A method of detecting an analyte in a liquid sample, the method comprising the steps of: 
       ( a )  providing a solid support comprising:    
       
         sorbent material, in the form of a test strip having a first portion, a second portion and a third portion, and providing flow from said first portion to said second portion and to said third portion,  
       
       
         a sample application site in said first portion of said test strip,  
       
       
         a visual inspection site in said second portion immobilizing therein a binder comprising a protein capable of binding at least the analyte or analogue thereof,  
       
       
         an additional visual inspection site in said third portion, and,  
       
       
         a tracer site comprising a dried reagent, supported on said test strip upstream of said second portion, consisting essentially of a tracer comprising colored particulate material conjugated to a ligand capable of binding one of the analyte and binder;  
       
       ( b )  applying to said sample application site said liquid sample;    
       ( c )  transporting said liquid sample along said test strip by capillary action, wicking or wetting into contact with said tracer to produce an admixture of said liquid sample and said tracer, and thereafter transporting said admixture into contact with said visual inspection sites thereby to produce    
       
         at said visual inspection site in said second portion, when said analyte is present in said liquid sample, a specific binding reaction product comprising a concentration of said tracer to produce a color visible to the unaided eye indicative of the presence of said analyte, and  
       
       
         at said additional visual inspection site in said third portion, visual indication of the presence or absence of analyte in the liquid sample. 
       
     
     
       25. The method according to  claim 24  wherein the colored particulate material is selected from the group consisting of colloidal metals, colored liposomes, colored polymeric beads and polymerized dye molecules. 
     
     
       26. The method according to  claim 25  wherein the colored particulate material is a colloidal metal. 
     
     
       27. The method according to  claim 25  wherein the colored particulate material is a colored liposome. 
     
     
       28. The method according to  claim 25  wherein the colored particulate material is a colored polymeric bead. 
     
     
       29. The method according to  claim 25  wherein the colored particulate material is a polymerized dye molecule. 
     
     
       30. The method according to  claim 24  wherein the analyte is an antigen and the ligand and the binder are antibodies thereto. 
     
     
       31. The method according to  claim 24  wherein the ligand and the binder are antigens or analogs thereof and the analyte is an antibody thereto. 
     
     
       32. The method according to  claim 24  wherein the tracer site is spatially separate from the sample application site in the first portion.