Multiplanar Lateral Flow Assay with Sample Compressor

Abstract

A sample compressor applies pressure to a sample collector and a sample application zone of a test strip to transfer a sample from the sample collector and a binding partner of an analyte to the sample application zone in a lateral flow device. At least one of the binding partners of the analyte is not located on the test strip prior to use of the lateral flow device. The test strip may be a universal test strip with no molecule that specifically binds the analyte is located on the test strip. The sample compressor may be a universal sample compressor also with no molecule that specifically binds the analyte on the sample compressor. The lateral flow device may also include one or more enhancement elements, where the enhancement elements bind to the analyte sandwich to increase a detection signal in the test zone.

1 - 10 . (canceled) 
     
     
         11 . A universal test strip for use in a lateral flow device, the universal test strip comprising a test zone and comprising no molecule which specifically binds an analyte. 
     
     
         12 . The universal test strip of  claim 11  further comprising a control zone and a control binding partner immobilized in the control zone. 
     
     
         13 . The universal test strip of  claim 11  further comprising a tag immobilized in the test zone. 
     
     
         14 . The universal test strip of  claim 11 , wherein the tag comprises a molecule selected from the group consisting of biotin, avidin, neutravidin, streptavidin, a lectin, and a glycosyl moiety. 
     
     
         15 . A sample compressor for use in a lateral flow device, the sample compressor comprising a pad and at least one binding partner on the pad, wherein the binding partner binds an analyte. 
     
     
         16 . The sample compressor of  claim 15  further comprising a mobile control binding partner on the pad. 
     
     
         17 . A universal sample compressor for use in a lateral flow device, the sample compressor comprising a pad and a mobile control binding partner on the pad, but comprising no molecule which specifically binds an analyte. 
     
     
         18 - 37 . (canceled) 
     
     
         38 . A method of enhancing a signal on a lateral flow device comprising a lateral flow chromatographic test strip comprising a sample application zone and a test zone, a conjugate comprising a first binding partner for an analyte in a sample and a label, a second binding partner for the analyte; and an enhancement element, comprising the steps of:
 a) immobilizing a sandwich formed between the analyte, if present in the sample, the conjugate, and the second binding partner in the test zone of the lateral flow chromatographic test strip; and   b) binding the enhancement element to the sandwich such that the enhancement element increases a detection signal in the test zone.   
     
     
         39 . The method of  claim 38 , wherein step b) comprises the substep of adding the enhancement element directly to the test zone after the sandwich has reached the test zone. 
     
     
         40 . The method of  claim 38 , wherein the enhancement element is in a volatile liquid. 
     
     
         41 . The method of  claim 38 , wherein the conjugate further comprises colloidal gold and the enhancement element comprises at least one silver salt. 
     
     
         42 . The method of  claim 38 , wherein the enhancement element comprises an antigen and the conjugate further comprises a specific binding partner for the antigen. 
     
     
         43 . The device of  claim 38 , wherein the enhancement element further comprises a label. 
     
     
         44 . The method of  claim 38 , wherein the test zone comprises no molecule which specifically binds the analyte. 
     
     
         45 . A method of detecting at least one analyte in a sample using a point-of-care assay device, the method comprising the steps of:
 a) adding a sample to a sample application zone of a lateral flow chromatographic test strip;   b) after step a), adding at least one labeled first binding partner for the analyte to the sample application zone such that, if the analyte is present in the sample, a first analyte complex forms between the first binding partner and the analyte;   c) exposing the sample to at least one second tagged binding partner for the analyte;   wherein, when the analyte is present, steps a) through c) result in the formation of a second analyte complex between the first binding partner, the analyte, and the second binding partner; and   d) capturing the second analyte complex with an immobilized tag in a detection zone of the lateral flow chromatographic test strip laterally downstream from the sample application zone; wherein the immobilized tag complexes with a tag portion of the second binding partner.   
     
     
         46 . The method of  claim 45 , wherein the first analyte complex forms without an addition of buffer to the test strip. 
     
     
         47 . The method of  claim 46 , wherein the second analyte complex forms without the addition of buffer to the test strip. 
     
     
         48 . The method of  claim 45 , wherein the point-of-care device comprises the lateral flow chromatographic test strip, a sample compressor comprising at least the labeled first binding partner, and a sample collector for collecting the sample, wherein the sample compressor, the sample collector, and the lateral flow chromatographic test strip form a vertical stack to apply the sample to the test strip by compression. 
     
     
         49 . The method of  claim 48 , wherein the sample collector delivers the sample passively by contact or through pressure onto the test strip prior to applying the sample compressor to the vertical stack. 
     
     
         50 . The method of  claim 45 , wherein a tag on the second binding partner and the immobilized tag comprise a pair selected from the group consisting of:
 a) a first biotin tag and a second immobilized tag selected from the group consisting of avidin, neutravidin and streptavidin;   b) a first tag selected from the group consisting of avidin, neutravidin and streptavidin and a second biotin immobilized tag;   c) a first lectin tag and a second glycosyl moiety immobilized tag; and   d) a first glyosyl moiety tag and a second lectin immobilized tag.   
     
     
         51 - 52 . (canceled)