Assay utilizing magnetic particles

• US 6,235,491 B1
• Filed: 11/19/1999
• Issued: 05/22/2001
• Est. Priority Date: 04/18/1997
• Status: Expired due to Fees

• Current Assignee: BYK Gulden Italia S.p.A.
• Original Assignee: BYK Gulden Italia S.p.A.
• Inventors: Connolly, Patricia
• Primary Examiner(s): Leary, Louise N.
• Application Number:
  US09/403,012
• Time in Patent Office: 550 Days
• Field of Search: 435/12, 435/14, 435/975, 435/25, 435/7.91, 435/4, 435/7.1, 205/787.5, 204/175
• US Class Current: 435/12
• 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 33/54333 Modification of conditions of immunological binding reaction, e.g. use of more than one type of particle, use of chemical agents to improve binding, choice of incubation time or application of magnetic field during binding reaction
• CPC Class Codes: G01N 33/84 involving inorganic compounds or pH

Abstract

An assay for the presence of an analyte or determining a biological or medical parameter comprising the steps of adding an assay component to a pH-sensitive material charged with magnetic particles, wherein the assay component causes a pH change which is a function of the analyte or parameter to be measured; subjecting the magnetic particles to an oscillating magnetic field; and measuring the effect of the magnetic field on the magnetic particles. The assay is an enzyme immunoassay. A kit for practicing the enzyme immunoassay is also described.

Claims

1. An assay for the presence of an analyte or determining a biological or medical parameter comprising:

adding an assay component to a pH-sensitive material charged with magnetic particles, wherein the assay component causes a pH change which is a function of the analyte or parameter to be measured;

subjecting the magnetic particles to an oscillating magnetic field; and

measuring the effect of the magnetic field on the magnetic particles.

2. The assay according to claim 1 wherein the assay component results from the interaction of the sample to be assayed with a reactive species.

5. The assay according to claim 2 wherein the reactive species is urease or glucose oxidase.

6. The assay according to claim 1 wherein the assay component is a hydroxyl radical.

7. The assay according to claim 1 wherein the pH-sensitive material is an enteric polymer, acetate hydrogen phthalate, a methyl vinyl ether-maleic anhydride ester, an anionic polymerisate of or an ester of.

8. The assay according to claim 1 wherein the assay is an immunoassay.

9. A kit for performing the assay of any of claims 1-8 comprising a reaction chamber containing magnetic particles captured in an pH-sensitive material, means for generating a magnetic field and detection means.

13. The assay according to claim 5 wherein the reactive species is urease or glucose oxidase.

14. The assay according to claim 7 wherein the pH-sensitive material is an enteric polymer selected from the group consisting of cellulose acetate hydrogen phthalate, a methyl vinyl ether-maleic anhydride ester, an anionic polymerisate of methacrylic acid and an ester of methacrylic acid.

15. The assay according to claim 1 wherein the assay is an enzyme immunoassay.

3. An assay for the presence of an analyte, comprising:

contacting a sample to be assayed for the presence of an analyte with a reactive species, the analyte interacting with the reactive species resulting in a change in pH;

directly or indirectly effecting a reaction with a pH-sensitive material which is charged with magnetic particles;

applying a magnetic field to the magnetic particles;

monitoring a response of said magnetic particles to the magnetic field; and

determining the amount of analyte in said sample by analysis of the response of the magnetic particles.

11. The assay according to claim 3 wherein the reactive species is urease or glucose oxidase.

4. An assay for determining a biological or medical parameter, comprising:

contacting a sample to be assayed for a biological or medical parameter with a reactive species, the sample interacting with the reactive species resulting in a change in pH;

directly or indirectly effecting a reaction with a pH-sensitive material which is charged with magnetic particles;

applying a magnetic field to the magnetic particles;

monitoring a response of said magnetic particles to the magnetic field; and

determining the parameter by analysis of the response of the magnetic particles.

12. The assay according to claim 4 wherein the reactive species is urease or glucose oxidase.

10. A binding pair assay in which a binding pair reaction produces a pH which is a function of the presence of an analyte in a sample or biological or medical parameter of a sample, and which comprises detecting liberation of magnetic particles from a pH-sensitive material.