Immunoassay probe

• US 20030194799A1
• Filed: 04/10/2003
• Published: 10/16/2003
• Est. Priority Date: 04/12/2002
• Status: Active Grant

• Current Assignee: Instrumentation Lab Co (Instrumentation Lab)
• Original Assignee: Instrumentation Lab Co (Instrumentation Lab)
• Inventors: Achter, Eugene K., Trotta, Stephen S., Schroeder, Hartmut Richard
• Granted Patent: US 7,514,270 B2
• Time in Patent Office: Days
• US Class Current: 435/287.2
• CPC Class Codes: B03C 1/288 disposed at the outer circumference of a recipient
• CPC Class Codes: B03C 2201/26 for use in medical or biological 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: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10T 436/113332 with conveyance of sample along a test line in a container or rack

Abstract

An analytical instrument for the immobilization of antigens to be detected in an immunoassay using mangetizable beads. The instrument includes a probe containing magnetizable particles and a plurality of magnetic devices for applying a magnetic field gradient to the particles in the probe reservoir. The probe is movable between the plurality of magnetic devices and at least one of the probe positions may be used to immobilize the magnetic particles in the fluid medium and at least another position may be used to resuspend the particles in a fluid medium.

Claims

1. A device for manipulating a magnetizable particle in a solution, comprising:

a probe for holding and transporting said magnetizable particles, said probe is transportable in a plurality of positions;

a first magnet for generating a first magnetic field; and

a second magnet for generating a second magnetic field, wherein said plurality of probe positions comprises positions between said first and second magnets.

2. The device according to claim 1 wherein at least one of said probe positions immobilizes said magnetizable particles in said solution, and at least another one of said positions resuspends said particles in said solution.

3. The device according to claim 1 wherein said probe comprises an inner wall and said magnetizable particles are immobilized against the inner wall of said probe.

4. The device according to claim 3 wherein said inner wall comprises a flat surface.

5. The device of claim 1 wherein the magnitude of said first magnetic field is different than the magnitude of said second magnetic field.

6. The device according to claim 1 wherein said plurality of probe positions comprises three positions.

7. The device according to claim 6 wherein one of said probe positions comprises a resuspend position.

8. The device according to claim 1 further comprising a transport stage for transporting said probe.

9. The device according to claim 1 further comprising a dilutor assembly, wherein said dilutor assembly introduces a fluid into a top end of the probe, and wherein the top end of the probe is opposite to an end of said probe for receiving a sample.

10. The device according to claim 1 wherein said probe further comprises a thermal control element.

11. The device according to claim 1 wherein said probe further comprises a liquid level sensing element.

12. The device according to claim 1 wherein said first magnet is in the range of about 1.0 to 5.0 times the strength of the second magnet.

13. The device according to claim 1 wherein the first magnet and the second magnet are separated by a gap in the range of about 1.5 to 2.5 inches.

14. The device according to claim 1 wherein the strength of the first magnet is in the range of about 1.0-2.0 times the strength of the second magnet.

15. The device according to claim 1 wherein the first magnet and the second magnet are separated by a gap of about 1.95 inches.

16. The device according to claim 9 wherein said dilutor assembly introduces fluid to a receiving end of said probe.

17. A method for washing a magnetizable particle, comprising the steps of:

aspirating a fluid sample comprising magnetizable particles into a probe, wherein said probe is transportable to a plurality of positions and joined to a transportation stage;

transporting said probe joined to said transporting stage to a magnetic washing station, said magnetic washing station comprising a first magnet for generating a first magnetic field and a second magnet for generating a second magnetic field and washing said magnetizable particle.

18. The method of claim 17 further comprising the steps of:

moving said probe to a capture position;

moving said probe from said capture position to a resuspend position; and

expelling said magnetizable particles from said probe.

19. The method of claim 18 further comprising:

moving said probe from a resuspend position to a neutral position; and

transporting said probe away from said magnetic washing station.

20. The method of claim 18 further comprising the step of flushing the lumen of said probe in said capture position with a diluent from a dilutor assembly.

21. The method of claim 20 wherein said diluent for flushing is introduced at a second end of said probe and expelled at a first end of said probe.

22. The method of claim 17 wherein said magnetizable particles are aspirated from a container.

23. The method of claim 22 wherein said container is a microtiter well.

24. The method of claim 18 wherein said magnetizable particles are expelled into a container.

25. The method of claim 24 wherein said container is a microtiter well.

26. The method of claim 17 further comprising the step of incubating said magnetizable particles with a body fluid.

27. The method of claim 17 further comprising the step of performing an immunoassay.

28. The method of claim 18 wherein said resuspend position is closer to said second magnet than said neutral position.

29. A method for manipulating a magnetizable particle in a solution, comprising the steps of:

introducing said particles into a probe;

immobilizing said particles in said probe by a first magnetic field; and

resuspending said particles in said probe by a second magnetic field.