Apparatus and method for processing magnetic particles

• US 6,884,357 B2
• Filed: 11/08/2002
• Issued: 04/26/2005
• Est. Priority Date: 02/21/1995
• Status: Expired due to Term

• Current Assignee: Sigris Research Incorporated
• Original Assignee: Sigris Research Incorporated
• Inventors: Siddiqi, Iqbal Waheed
• Primary Examiner(s): Reifsnyder, David A.
• Application Number:
  US10/290,514
• Publication Number:
  US 20030127396A1
• Time in Patent Office: 900 Days
• Field of Search: 210/695, 210/222, 366/273
• US Class Current: 210/695
• CPC Class Codes: B01F 33/451 wherein the mixture is directly exposed to an electromagnetic field without use of a stirrer, e.g. for material comprising ferromagnetic particles or for molten metal
• CPC Class Codes: B01F 33/81 Combinations of similar mixers, e.g. with rotary stirring devices in two or more receptacles
• CPC Class Codes: B01F 33/813 mixing simultaneously in two or more mixing receptacles
• CPC Class Codes: B01L 9/523 for multisample carriers, e.g. used for microtitration plates
• CPC Class Codes: B03C 1/01 by addition of magnetic adjuvants
• CPC Class Codes: B03C 1/12 with magnets moving during operation; with movable pole pieces
• CPC Class Codes: B03C 1/14 with non-movable magnets
• CPC Class Codes: B03C 1/24 with material carried by travelling fields
• CPC Class Codes: B03C 1/288 disposed at the outer circumference of a recipient
• CPC Class Codes: B03C 2201/18 Magnetic separation whereby the particles are suspended in a liquid
• CPC Class Codes: B03C 2201/26 for use in medical applications
• CPC Class Codes: G01N 35/0098 involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation magnetic particles used in immunoassays G01N33/54326; magnetic separation in general B03C
• CPC Class Codes: Y10T 436/25 including sample preparation
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

An apparatus and method for carrying out the affinity separation of a target substance from a liquid test medium by mixing magnetic particles having surface immobilized ligand or receptor within the test medium to promote an affinity binding reaction between the ligand and the target substance. The test medium with the magnetic particles in a suitable container is removably mounted in an apparatus that creates a magnetic field gradient in the test medium. This magnetic gradient is used to induce the magnetic particles to move, thereby effecting mixing. The mixing is achieved either by movement of a magnet relative to a stationary container or movement of the container relative to a stationary magnet. In either case, the magnetic particles experience a continuous angular position change with the magnet. Concurrently with the relative angular movement between the magnet and the magnetic particles, the magnet is also moved along the length of the container causing the magnetic field gradient to sweep the entire length of the container. After the desired time, sufficient for the affinity reaction to occur, movement of the magnetic gradient is ended, whereby the magnetic particles are immobilized on the inside wall of the container nearest to the magnetic source. The remaining test medium is removed while the magnetic particles are retained on the wall of the container. The test medium or the particles may then be subjected to further processing.

Claims

1. A process of mixing and separating magnetic particles comprising;

providing at least one container having a liquid and said particles therein;

providing at least two linear staggered magnetic sources near said at least one container;

providing cyclic relative linear motion between said two staggered magnetic sources and said container;

stopping said relative motion whereby said particles become immobilized as a relatively compact mass aggregate on the inside wall of said one container nearest a magnetic source.

2. The process of claim 1, wherein said particles carry immobilized ligand or receptors to promote an affinity binding reaction between said particles and a target substance.

3. The process of claim 1, wherein said movement is continuous.

4. The process of claim 1, wherein said movement is step-wise.

5. The process of claim 1, wherein said movement is a combination of continuous and step-wise movements.

6. A process of mixing and separating magnetic particles comprising:

providing an array of containers having a liquid and said particles therein;

providing two arrays of staggered magnetic sources near said array of containers;

providing cyclic relative linear movement between said array of containers and said two arrays of staggered magnetic sources; and

stopping said relative movement whereby said particles become immobilized as a relatively compact mass aggregate on the inside walls of said containers nearest said magnetic sources.

7. The process of claim 6, wherein said arrays are linear arrays and said movement is a horizontal movement.

8. The process of claim 6, wherein said arrays are linear arrays and said movement is a vertical movement.

9. A process of mixing and separating magnetic particles comprising:

providing an array of containers;

each said container having a liquid and said particles therein;

providing at least two staggered arrays of magnetic sources;

providing support for said array of containers and said arrays of magnetic sources;

providing relative movement between said array of containers and said arrays of magnetic sources to bring about resuspension and mixing of said particles; and

stopping said movement whereby said particles become immobilized as a relatively compact aggregate on inside walls of said containers nearest said magnetic sources.

10. The process of claim 9 wherein said movement is a horizontal linear movement.

11. The process of claim 9 wherein said movement is a linear vertical movement.

12. The process of claim 9 wherein said movement is a rotary movement.

13. The process of claim 9 wherein said movement is step-wise.

14. The process of claim 9 wherein said array of containers is mobile and said arrays of magnetic sources are stationary.

15. The process of claim 9 wherein said array of containers is stationary and said arrays of magnetic sources are mobile.