Device and method for integrated diagnostics with multiple independent flow paths

• US 6,436,722 B1
• Filed: 04/18/2000
• Issued: 08/20/2002
• Est. Priority Date: 04/18/2000
• Status: Expired due to Fees

• Current Assignee: IDEXX Laboratories Incorporated
• Original Assignee: IDEXX Laboratories Incorporated
• Inventors: Suva, Robert H., Barski, Stanislaw Jr., Clark, Scott M., Workman, Erwin F. Jr., Kepron, Michael R.
• Primary Examiner(s): Ceperley, Mary E.
• Assistant Examiner(s): Padmanabhan, Kartic
• Application Number:
  US09/551,496
• Time in Patent Office: 854 Days
• Field of Search: 422/50, 422/55, 422/56, 422/58, 422/63, 422/68.1, 422/83, 422/88, 422/102, 422/119, 422/255, 422/256, 422/261, 422/283, 422/919, 422/947, 435/6, 435/7.1, 435/7.92, 435/174, 435/176, 435/177, 435/287.1, 435/287.2, 435/287.3, 435/287.7, 435/288.1, 435/288.5, 435/288.7, 436/43, 436/55, 436/169, 436/178, 436/512, 436/518, 436/524, 436/527, 436/528, 436/536, 436/541
• US Class Current: 436/518
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01N 33/54388 based on lateral flow
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: Y10T 436/11 Automated chemical analysis
• CPC Class Codes: Y10T 436/12 Condition responsive control
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction

Abstract

Invention performs an assay to determine presence or quantity of specific analyte in fluid sample. Representative device has two separate flow paths established sequentially in device with a single user activation step. First flow path delivers sample, and conjugate soluble binding reagents to solid phase. If analyte is present, an analyte:conjugate complex is formed and immobilized. Sample volume delivered by first path determined by absorbent capacity of solid phase, and not by amount of sample added to device. User need not measure sample volume. Sample/conjugate mixture is prevented from entering second flow path because capillary and surface energy of second flow path prevent it from being wetted by this mixture. Second flow path allows wash reagent to remove unbound conjugate and sample from solid phase to the absorbant, and optionally deliver detection reagents. Adaptable for many formats including, sandwich immunoassays, colloidal gold, sol particle, heterogeneous generic capture, and competitive assays.

Claims

1. A device for performing an assay which determines a presence or quantity of an analyte in a liquid sample (1) using a solid phase for capturing said analyte or the analyte bound to a binding partner for the analyte, and (2) detecting binding of said analyte or said analyte bound to its binding partner after washing unbound material from said solid phase, said device comprising:

(a) a first flow path for sample entry and delivery to a solid phase zone (c);

(b) a second flow pot comprising a fluid path material, said fluid path material essentially impermeable to said liquid sample, but which defines a second flow path for said sample when made permeable by contact with a wash reagent, wherein said second flow path is independent of said first flow path;

(c) a solid phase zone permeable to said liquid sample, at an intersection between said first and second flow paths, wherein said solid phase zone comprises a binding partner for said analyte or said analyte bound to its binding partner, and said solid phase is used in both capture and detection of said analyte or said analyte bound to its binding partner,

whereby said liquid sample initially flows only along said first flow path into said sold phase zone but not into said fluid path material until said fluid path material is rendered hydrophilic by introduction of said wash reagent into said second flow path, whereby said wash reagent removes unbound material from said solid phase zone through said second flow path; and

(d) a means to test a single sample for a single analyte or a means to test a single sample for multiple analytes.

2. Device of claim 1 wherein said first flow path is through a capillary space called a sample delivery channel.

3. Device of claim 1 wherein said first flow path comprises a bibulous material.

4. Device of claim 1 wherein said first flow path is through a sample delivery channel containing dried conjugate soluble binding reagents.

5. Device of claim 1 wherein said binding partners for the assays include antigens, antibodies, ligands, receptors, nucleic acid molecules, chemical reactants, and fragments thereof.

6. Device of claim 1 further comprising conjugate soluble binding reagents dried in the sample delivery channel.

7. Device of claim 1 further comprising at least one conjugate soluble binding reagent added to the sample prior to adding said sample to said device.

8. Device of claim 1 wherein the assay involves an immobilized reactant or substrate on the solid phase, and detection occurs on said solid phase.

9. Device of claim 1 wherein the assay involves having the reactant or substrate in said first flow path and detection occurs on said solid phase.

10. Device of claim 1 wherein the solid phase is selected from the group consisting of:

glass fiber mats, non-woven synthetic mats, sintered particulate structures, cast membrane materials, extruded membrane materials, materials characterized by the presence of adhesion within the material, molded open pore nylon structure, cast open pore nylon structure, molded open pore nitrocellulose structure, cast open pore nitrocellulose structure, particulate material of glass particles, particulate material of polymer particles, and an electrochemical detector.

11. Device of claim 1 wherein said wash reagent is delivered from at least one pierceable container following activation of said device, said wash reagent is selected from the group consisting of at least one wash reagent, at least one substrate reagent, at least one wash reagent and at least one substrate reagent, and at least one wash/substrate reagent.

12. Device of claim 1 further comprising an absorbent block comprised of an absorbent material independent of said fluid path material.

13. Device of claim 1 wherein said second flow path is through bibulous material or plastic.

14. Device of claim 1 further comprising a sample entry port located upstream of the solid phase or directly above the solid phase and sample is applied via a cup structure or a sample absorbing tip.