Immuno gold lateral flow assay

Abstract

A chromatographic specific binding assay strip device, comprising: a non-permeable platform strip; a permeable membrane testing strip positioned on top of said non-permeable platform strip, with the testing strip comprising at least one capture reagent site containing a capture reagent for at least one specific analyte, a sample receiving pad positioned on top of and at a proximal end of the non-permeable platform strip, with the sample receiving pad having contact with a proximal end of said permeable membrane testing strip, a reservoir pad positioned on top of and at a distal end of said non-permeable membrane testing strip, with the reservoir pad having contact with a proximal end of said permeable membrane test strip; a supporting strip attached to and extending from the proximal end of said non-permeable platform strip; and a conjugate pad positioned on said supporting strip, said conjugate pad comprising a semi-permeable membrane containing a colorant conjugate. The semi-permeable membrane acts as a barrier between the conjugate pad and the sample receiving pad, regulating the flow through the semi-permeable membrane and overall flow of the assay By dipping the conjugate pad into a sample solution, there will be increased binding between the analyte in the sample and the conjugate (preferably colloidal gold), thereby giving improved results on the lateral flow assay.

1 . A chromatographic specific binding assay strip device, comprising:
 a) a non-permeable platform strip;   b) a permeable membrane testing strip positioned on top of said non-permeable platform strip, said testing strip comprising at least one capture reagent site specific for an analyte being tested;   c) at least one capture reagent positioned at said capture reagent site;   d) a sample receiving pad positioned on top of and at a proximal end of the non-permeable platform strip, said sample receiving pad having contact with a proximal end of said permeable membrane testing strip;   e) a reservoir pad positioned on top of and at a distal end of said non-permeable membrane testing strip, said reservoir pad having contact with a distal end of said permeable membrane test strip;   f) a supporting strip attached to and extending from the proximal end of said non-permeable platform strip; and   g) a conjugate pad positioned on said supporting strip, said conjugate pad comprising a permeable membrane containing a colorant conjugate.   
     
     
         2 . The chromatographic specific binding assay strip device according to  claim 1 , wherein said supporting strip is a membrane. 
     
     
         3 . The chromatographic specific binding assay strip device according to  claim 2 , wherein said membrane is a semi-permeable membrane. 
     
     
         4 . The chromatographic specific binding assay strip device according to  claim 1 , wherein said semi-permeable membrane is constructed of a material selected from the group consisting of micro-porous plastics, fibers, fabrics, metallic fabrics, fibers, plastics coated with hydrophobic material, hatched poly-fibers creating micro-pores, spun polyethylene, spun polypropylene and combinations thereof. 
     
     
         5 . The chromatographic specific binding assay strip device according to  claim 3 , wherein said conjugate pad is positioned on the underside of said semi-permeable membrane. 
     
     
         6 . The chromatographic specific binding assay strip device according to  claim 1 , wherein said reservoir pad is fibrous. 
     
     
         7 . The chromatographic specific binding assay strip device according to  claim 1 , wherein said conjugate of said conjugate pad is selected from the group consisting of latex microparticles, enzymatic, fluorescent, metal sols, and colloidal gold particles. 
     
     
         8 . The chromatographic specific binding assay strip device according to  claim 7 , wherein said conjugate of said conjugate pad is a colloidal gold. 
     
     
         9 . The chromatographic specific binding assay strip device according to  claim 1 , wherein said binding assay strip device is enclosed in a cassette, said cassette having an opening to view results of a test of a sample. 
     
     
         10 . The chromatographic specific binding assay strip device according to  claim 1 , further comprising a control site on the permeable membrane testing strip. 
     
     
         11 . The chromatographic specific binding assay strip device according to  claim 1 , wherein said device contains blocked bovine serum albumin and detergent to prevent loss of antibody. 
     
     
         12 . A method of detecting the presence or absence of an analyte or ligand in a liquid sample comprising:
 a) preparing a liquid sample;   b) transferring the liquid sample to a container having an opening;   c) obtaining a chromatographic specific binding assay strip device, said binding assay strip device comprising:
 i) a non-permeable platform strip; 
 ii) a permeable membrane testing strip positioned on top of said non-permeable platform strip, said testing strip comprising at least one capture reagent site specific for an analyte being tested; 
 iii) a capture reagent positioned at said capture reagent site; 
 iv) a sample receiving pad positioned on top of and at a proximal end of the non-permeable platform strip, said sample receiving pad having contact with a proximal end of said permeable membrane testing strip; 
 v) a reservoir pad positioned on top of and at a distal end of said non-permeable membrane testing strip, said reservoir pad having contact with a end of said permeable membrane test strip; 
 vi) a supporting strip attached to and extending from the proximal end of said non-permeable platform strip; and 
 vii) a conjugate pad positioned on said supporting strip, said conjugate pad comprising a permeable membrane containing a colorant conjugate; 
   d) inserting the support strip comprising said conjugate pad into the liquid sample;   e) allowing enough time for formation of a conjugated sample;   f) pushing the chromatographic specific binding assay strip device further into the liquid comprising the conjugated sample, such that the sample receiving pad is now in said solution;   g) allowing time for the solution containing the conjugated sample to move laterally along the permeable membrane testing strip; and   h) observing any results on the permeable membrane testing strip.   
     
     
         13 . A chromatographic specific binding assay strip device is disclosed, comprising:
 a) a non-permeable platform strip;   b) a permeable membrane testing strip positioned on top of the non-permeable platform strip;   c) a sample receiving pad positioned on top of and at a proximal end of the non-permeable platform strip while in contact with a proximal end of the permeable membrane testing strip;   d) a reservoir pad positioned on top of and at a distal end of the non-permeable membrane testing strip while in contact with a distal end of said permeable membrane test strip;   e) a semi-permeable membrane positioned on top of said sample pad; and   f) a conjugate pad positioned on top of said semi-permeable membrane, said conjugate pad comprising a permeable membrane containing a conjugate.   
     
     
         14 . The chromatographic specific binding assay strip device according to  claim 13 , wherein said reservoir pad is fibrous. 
     
     
         15 . The chromatographic specific binding assay strip device according to  claim 13 , wherein said conjugate of said conjugate pad is selected from the group consisting of latex microparticles, enzymatic, fluorescent, metal sols, and colloidal gold particles. 
     
     
         16 . The chromatographic specific binding assay strip device according to  claim 15 , wherein said conjugate of said conjugate pad is a colloidal gold. 
     
     
         17 . The chromatographic specific binding assay strip device according to  claim 13 , wherein said binding assay strip device is enclosed in a cassette, said cassette having an opening to view results of a test of a sample. 
     
     
         18 . The chromatographic specific binding assay strip device according to  claim 13 , further comprising a control site on the permeable membrane testing strip. 
     
     
         19 . The chromatographic specific binding assay strip device according to  claim 13 , wherein said device contains blocked bovine serum albumin and detergent to prevent loss of antibody, by non-specific attachment. 
     
     
         20 . A method of detecting the presence or absence of an analyte or ligand in a liquid sample comprising: a) obtaining a sample fluid; b) obtaining a chromatographic specific binding assay strip device, said device comprising: i) a non-permeable platform strip; ii) a permeable membrane testing strip positioned on top of the non-permeable platform strip; iii) a sample receiving pad positioned on top of and at a proximal end of the non-permeable platform strip while in contact with a proximal end of the permeable membrane testing strip; iv) a reservoir pad positioned on top of and at a distal end of the non-permeable membrane testing strip while in contact with a distal end of said permeable membrane test strip; v) a semi-permeable membrane positioned on top of said sample pad; and vi) a conjugate pad positioned on top of said semi-permeable membrane, said conjugate pad comprising a permeable membrane containing a conjugate.