Magnetic bead aggregation assay system

Patent metadata

Field	Value
Publication number	US-10386364-B2
Application number	US-201214131328-A
Country	US
Kind code	B2
Filing date	Jul 9, 2012
Priority date	Jul 7, 2011
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

There is provided a method of aggregating a plurality of beads in a magnetic bead aggregation assay for subsequent analysis comprising: —providing magnetic beads comprising a capture probe for binding with said target analyte; —reacting the magnetic beads with the sample including a target analyte in a reaction chamber aggregating the magnetic beads in the presence of a magnetic field with the target analyte to allow formation of magnetic bead aggregates having physical properties detectable to enable characterization of the aggregates on an aggregate by aggregate basis using a detector to measure the physical properties of the aggregates. Further provided are a method and system for detecting analytes in a sample by characterizing the magnetic bead aggregates on an aggregate by aggregate basis by measuring physical properties of the aggregates.

First claim

The invention claimed is:

1. A method of aggregating a plurality of beads for subsequent analysis comprising:
providing a container, defining a reaction chamber, with a sample solution and a plurality of beads in the sample solution, wherein the plurality of beads comprises magnetic beads of a first type comprising a capture probe for binding with a first analyte and magnetic beads of a second type comprising a capture probe for binding with a second analyte, the magnetic beads of the first type and the magnetic beads of the second type being uniform in their physical properties of magnetization, color and size and comprising carboxyl coated particles modified with a protective polyethylene glycol (PEG) layer;
incubating the beads with the first analyte and the second analyte;
applying a magnetic field of a first orientation to the reaction chamber containing the sample solution;
allowing the beads to migrate to and collect on a side surface of the container in the presence of a magnetic field of a first orientation until the beads have separated from the sample solution;
subsequent to collecting the beads on the side surface of the container, replacing the sample solution with a new second solution in the container and stirring the second solution to suspend the beads;
reapplying the magnetic field of the first orientation to the second solution and the beads and collecting the beads on the side surface of the container for a second time;
exposing the beads to a magnetic field of a second orientation to allow formation of aggregates of the beads and the analytes by increasing the bead to bead interactions, comprising moving the beads relative to the magnetic field of the second orientation, wherein the container and the beads collected on the side of the container is rotated 90 degrees while maintaining the magnetic field of the second orientation such that the beads roll to the side of the container and settle on the side of the container as aggregates comprising monomer or dimer or trimer or tetramer aggregates; and
collecting the aggregates, wherein aggregates of the first type of magnetic beads and the first analyte and aggregates of the second type of magnetic beads and the second analyte each have predefined physical properties detectable to enable characterization of the aggregates of the first type of magnetic beads and the aggregates of the second type of magnetic beads on a bead by bead basis using a detector to measure the physical properties of the aggregates to detect the first and second analytes.

2. The method of claim 1 wherein the beads are super-paramagnetic beads.

3. The method of claim 1 wherein the magnetic beads further comprise a protein coating.

4. The method of claim 3 wherein the protein coated magnetic beads are coupled to a biotinylated nucleic acid probe.

5. The method of claim 3 wherein the protein is streptavidin.

6. The method of claim 1 wherein the aggregation of magnetic beads to form aggregates is controllable by controlling bead concentration.

7. The method of claim 1 wherein the aggregation of magnetic beads to form aggregates is controllable by controlling binding capacity.

8. The method of claim 1 wherein the magnetic beads are reacted with the sample for a reaction time and wherein aggregation of magnetic beads to form aggregates is controllable by controlling reaction time.

9. The method of claim 8 wherein an increased reaction time provides an increase in the aggregation rate.

10. The method of claim 1 further comprising the step of applying a magnetic force to provide the magnetic field for aggregating the magnetic beads wherein the aggregation of magnetic beads to form aggregates is controllable by controlling application of magnetic force.

11. The method of claim 1 wherein the PEG comprises a mixed butyloxycarbonyl (BOC) terminated PEG functionality.

12. The method of claim 11 wherein a streptavidin protein is conjugated onto the bead surface.

13. The method of claim 1 wherein the method is a reagent-free method.

14. A method of aggregating a plurality of beads for subsequent analysis comprising:
providing a container, defining a reaction chamber, with a sample solution and a plurality of beads, wherein the plurality of beads comprises magnetic beads of a first type comprising a capture probe for binding with a first analyte and magnetic beads of a second type comprising a capture probe for binding with a second analyte, the magnetic beads of the first type and the magnetic beads of the second type being uniform in their physical properties of magnetization, color and size and comprising carboxyl coated particles modified with a protective polyethylene glycol (PEG) layer;
incubating the beads with the analytes;
applying a magnetic field of a first orientation to the reaction chamber containing the sample solution and the beads;
allowing the beads to migrate to and collect on a side surface of the container, wherein the sample solution is left in the presence of a magnetic field of a first orientation until the beads have separated from the solution;
subsequent to collecting the beads on the side surface of the container, replacing the sample solution with a second solution and stirring the second solution with the collected beads;
re-applying the magnetic field of the first orientation, separating the beads from the second solution, and collecting the beads on the side surface of the container for a second time;
exposing the beads to a magnetic field of a second orientation to increase the bead interactions and increase the number of aggregates comprising the beads and the analytes, comprising maintaining the beads stationary while varying the direction of the magnetic field of the second orientation such that the beads roll to the side of the container and settle on the side of the container forming aggregates comprising monomer or dimer or trimer or tetramer aggregates; and
collecting the aggregates, wherein aggregates of the first type of magnetic beads and the first analyte and aggregates of the second type of magnetic beads and the second analyte each have predefined physical properties detectable to enable characterization of the aggregates of the first type of magnetic beads and the aggregates of the second type of magnetic beads on a bead by bead basis using a detector to measure the physical properties of the aggregates to detect the first and second analytes.

15. The method of claim 14 wherein the method is a reagent-free method.

Assignees

• Lee Gil
• Li Peng
• Platt Mark
• Cannon Gemma
• Univ College Dublin Nat Univ Ireland Dublin

Inventors

• Lee Gil
• Li Peng
• Platt Mark
• Cannon Gemma

Classifications

• G01N33/54326 Primary

  Magnetic particles · CPC title

• B03C1/288

  disposed at the outer circumference of a recipient · CPC title

• B03C2201/24

  for measuring or calculating of parameters, e.g. efficiency · CPC title

• G01N33/54346 Primary

  Nanoparticles · CPC title

• G01N2446/84

  Polymer coating, e.g. gelatin · CPC title