Magnetic immunosensor and method of use

• US 9,233,370 B2
• Filed: 08/05/2011
• Issued: 01/12/2016
• Est. Priority Date: 08/05/2010
• Status: Active Grant

• Current Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Inventors: Miller, Cary James, Hu, Jinghua
• Primary Examiner(s): Brown, Melanie Y
• Assistant Examiner(s): MARTINEZ, REBECCA L
• Application Number:
  US13/204,121
• Publication Number:
  US 20120034633A1
• Time in Patent Office: 1,621 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B01L 2200/0684 Venting, avoiding backpressure, avoid gas bubbles
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2400/043 magnetic forces
• CPC Class Codes: B01L 2400/0481 squeezing of channels or chambers
• CPC Class Codes: B01L 2400/0683 mechanically breaking a wall or membrane within a channel or chamber
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 3/502761 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules investigating characteristics of particles G01N15/00
• CPC Class Codes: G01N 27/745 for detecting magnetic beads used in biochemical assays concerning the assays G01N33/54326; sensors therefor G01R33/1269; automatic analysers therefor G01N35/0098
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 33/5438 Electrodes

Abstract

The present invention provides apparatus and methods for the rapid determination of analytes in liquid samples by immunoassays incorporating magnetic capture of beads on a sensor capable of being used in the point-of-care diagnostic field.

Claims

1. A microfabricated magnetic layer on a substantially planar surface, wherein the microfabricated magnetic layer comprises:

high-field permanent magnetic particulates dispersed in a thermally, chemically or photoformably cured immobilization matrix;

wherein the immobilization matrix comprises a polyimide, polyvinyl alcohol, or epoxy resin;

wherein the microfabricated magnetic layer is positioned substantially proximate to a microfabricated sensing electrode,

wherein the electrode is connected by a conductive line to instrument electronics, wherein the microfabricated magnetic layer is not the conductive line,

wherein the microfabricated magnetic layer is positioned to attract magnetically susceptible beads coated with a capture antibody to a target analyte,

wherein the electrode is an amperometric electrode, and

wherein the magnetic layer is configured to concentrate the magnetically susceptible beads with the capture antibody and the target analyte within a sample fluid at the electrode for measurement, and

wherein the amperometric electrode is configured to detect the target analyte.

2. The microfabricated magnetic layer of claim 1, wherein the magnetic particulates comprise a neodymium iron boron (NdFeB) alloy.

3. The microfabricated magnetic layer of claim 1, wherein the magnetic particulates comprise a Nd₂Fe₁₄B alloy.

4. The microfabricated magnetic layer of claim 1, wherein the magnetic particulates have an average particle size of from 0.01 μ

m to 20 μ

m.

5. The microfabricated magnetic layer of claim 1, wherein the magnetic particulates have an average particle size of from 0.01 μ

m to 5 μ

m.

6. The microfabricated magnetic layer of claim 1, wherein the immobilization matrix comprises polyimide.

7. The microfabricated magnetic layer of claim 1, wherein the immobilization matrix comprises polyvinyl alcohol.

8. The microfabricated magnetic layer of claim 1, wherein the magnetic particulates provide a magnetic field of greater than about 0.1 Tesla.

9. The microfabricated magnetic layer of claim 1, wherein the microfabricated magnetic layer is positioned to yield an event horizon for the magnetically susceptible beads in the range of less than about 200 μ

m in the region of the electrode.

10. The microfabricated magnetic layer of claim 1, wherein the electrode is a gold microarray.

11. The microfabricated magnetic layer of claim 1, wherein the microfabricated magnetic layer is positioned over the substantially planar surface.

12. The microfabricated magnetic layer of claim 1, wherein the microfabricated magnetic layer is directly attached to the substantially planar surface.

13. The microfabricated magnetic layer of claim 1, wherein the microfabricated magnetic layer is coated onto the surface of the substantially planar surface.

14. The microfabricated magnetic layer of claim 1, wherein the microfabricated magnetic layer is patterned onto the surface of the substantially planar surface.

15. The microfabricated magnetic layer of claim 1, wherein the microfabricated magnetic layer is positioned proximate to the sensing electrode.