Displacement assay on a porous membrane

• US 6,808,937 B2
• Filed: 07/13/2001
• Issued: 10/26/2004
• Est. Priority Date: 01/11/1996
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Ligler, Frances S., Kusterbeck, Anne W., Rabbany, Sina Y.
• Primary Examiner(s): Chin, Christopher L.
• Assistant Examiner(s): Lam, Ann Y.
• Application Number:
  US09/907,888
• Publication Number:
  US 20020028475A1
• Time in Patent Office: 1,201 Days
• Field of Search: 435/7.95, 435/4, 435/287.3, 435/287.6, 435/287.7, 435/287.9, 435/288.1, 435/288.2, 435/288.4, 435/288.5, 435/283.1, 435/288.7, 435/287.1, 435/7.92, 435/7.93, 435/7.94, 435/287.8, 435/287.2, 436/518, 436/524, 436/535, 436/538, 436/539, 436/540, 436/541, 436/66, 436/67, 436/174, 436/177, 436/178, 422/50, 422/55, 422/61, 422/68.1, 422/58, 422/69, 422/82.05, 422/99, 422/101, 422/102, 422/83
• US Class Current: 436/518
• CPC Class Codes: G01N 33/54386 Analytical elements
• CPC Class Codes: G01N 33/54388 based on lateral flow

Abstract

Displacement assays, under non-equilibrium conditions, are performed by flowing a liquid sample through a membrane having binding elements with binding sites saturated with a labelled form of the analyte. Analyte in the sample displaces, under non-equilibrium conditions, the labelled form of the analyte from the membrane. The displaced labelled form of the analyte may then be detected.

Claims

1. A device for the immunoassay of an aqueous sample suspected of containing a target analyte, comprising:

a container, said container including an open end and a closed end;

a cap within which said open end of said container may be fitted in a first position in which the closed end of said container is a first distance from said cap and in a second position in which the closed end of said container is a second distance from said cap, said second distance being less than said first distance;

a tip for receiving said aqueous sample extending outwardly from said cap;

a hollow needle extending from said cap in a direction opposite to said tip;

a septum extending across the width of said container, said septum being positioned between said closed end of said container and an end of said needle distal to said cap when said container is seated in said first position, said septum being essentially impermeable to fluid;

a porous membrane positioned between said septum and said closed end of said container, said membrane extending across the width of said container, and an evacuated reservoir between said membrane and said closed end, said membrane having binding elements immobilized thereon, each of said binding elements having at least one binding site capable of specifically binding to said target analyte, essentially all of said binding sites on said binding elements being either occupied by a labelled analog of the target analyte to form complexes of membrane-immobilized binding elements and labelled analogs; and

a detector for detecting the presence of said labelled analog in said reservoir;

said hollow needle being positioned so as to puncture said septum, but not said membrane, when said container is in said second position.

2. The device of claim 1, further comprising a sample holder for holding a liquid sample therein, wherein said puncture of said septum causes liquid sample from sample holder to flow through said open end, through said membrane, and into said reservoir.