METHOD AND SYSTEM FOR MAGNETIC EXTRACTION OF COMPONENTS IN A LIQUID SAMPLE

• US 20190316114A1
• Filed: 11/25/2016
• Published: 10/17/2019
• Est. Priority Date: 05/03/2016
• Status: Active Grant

• Current Assignee: Biomerieux B.V. (Compagnie Merieux Alliance SAS)
• Original Assignee: Biomerieux B.V. (Compagnie Merieux Alliance SAS)
• Inventors: ALIX, David, MINASSIAN, Edgar, RAYMOND, Jean-Claude, WANDELS, Philippe
• Granted Patent: US 11,572,553 B2
• Time in Patent Office: Days
• CPC Class Codes: B01L 2300/041 Connecting closures to device or container
• CPC Class Codes: B01L 2300/0609 Holders integrated in container to position an object
• CPC Class Codes: B01L 2300/0848 Specific forms of parts of containers
• CPC Class Codes: B01L 3/0231 having several coaxial pistons
• CPC Class Codes: B01L 3/0275 Interchangeable or disposable dispensing tips
• CPC Class Codes: B01L 3/50853 with covers or lids
• CPC Class Codes: B01L 9/523 for multisample carriers, e.g. used for microtitration plates
• CPC Class Codes: B01L 9/543 for disposable pipette tips, e.g. racks or cassettes
• CPC Class Codes: C12N 15/1013 by using magnetic beads
• CPC Class Codes: C12Q 1/6806 Preparing nucleic acids for analysis, e.g. for polymerase chain reaction [PCR] assay C12Q1/6804 takes precedence
• CPC Class Codes: G01N 1/4077 by other techniques involving separation of suspended solids

Abstract

A system for extracting analytes from a biological sample, which includes: an electronic pipette having pipette cones with a tip; a well support; a pipette holder including: a base which can removably house each well support; a pipette support into which the pipette is inserted, and which can move relative to the base between a first position in which the tips of the cones are inserted in a well of the support and at least one second position in which the tips are outside the wells; a housing facing the pipette cones above their tip when the pipette support is in the first position, and facing the tips of the pipette cones when the pipette support is in the second position; and a magnetized part removably inserted in the housing.

Claims

1. A method for extracting components contained in a biological sample in liquid form, the components being capable of binding to magnetic particles, the method comprising:

a phase of mixing the sample with the magnetic particles;

a phase of suctioning the mixture from a well in a tubular pipette cone comprising a tip intended for pipetting liquid;

a phase of capturing the magnetic particles on an internal wall of the pipette cone;

by applying a first magnetic field to the pipette cone, the field being capable of attracting and holding the magnetic particles in a predetermined zone of the pipette cone, termed “

capture”

zone, above the tip of the cone;

and by applying at least one cycle of suction and discharge of the mixture contained in the pipette cone in a well;

at least one phase of washing the particles captured on the internal wall of the pipette cone by;

discharging the mixture contained in the pipette cone; and

applying, from a well containing a washing solution, at least one cycle of suction and discharge of the washing solution in the pipette cone;

a phase of migration of the magnetic particles on the internal wall of the pipette cone, from the capture zone to the tip of the pipette cone, by carrying out a relative movement of the pipette cone relative to the first magnetic field;

and a phase of transferring the magnetic particles having migrated into the tip of the pipette cone into a recovery well containing a solution.

2. The method as claimed in claim 1, wherein the movement of the first magnetic field consists in moving the pipette cone parallel to a longitudinal axis of the cone, and in keeping the first magnetic field constant, the longitudinal axis of the pipette cone remaining at equal distance from the first magnetic field during the movement of the pipette cone.

3. The method as claimed in claim 1, wherein the transferring phase comprises:

placing the tip of the pipette cone in the recovery well;

and applying a second magnetic field from the bottom of the recovery well so as to cause the magnetic particles contained in the tip of the pipette cone to migrate into the recovery well.

4. The method as claimed in claim 3, wherein the second magnetic field is produced by a magnet positioned partially or entirely under the tip of the pipette cone.

5. The method as claimed in claim 3, wherein the first magnetic field applied to the pipette cone is deactivated during the application of the second magnetic field.

6. The method as claimed in claim 3, wherein the transferring phase comprises the deactivation of the first magnetic field followed by the application of cycles of suction and discharge of the solution of the recovery well in the tip of the pipette cone, the application comprising:

a first phase of applying the cycles at a first frequency;

followed by a second phase of applying the cycles at a second frequency, lower than the first frequency.

7. The method as claimed in claim 1, comprising, prior to the capturing phase, a phase of stirring the mixture contained in the pipette cone by applying at least one cycle of suction and discharge of the mixture in the pipette cone.

8. The method as claimed in claim 1, comprising, prior to the transferring phase, at least one phase of washing the particles captured on the internal wall of the pipette cone by:

a. deactivating the magnetic field;

b. releasing the captured particles by applying, from a well containing a washing solution, at least one cycle of suction and discharge of the washing solution in the pipette cone;

c. applying a second phase of capturing on an internal wall of the pipette cone;

by applying the first magnetic field to the pipette cone,

and by applying at least one cycle of suction and discharge of the mixture contained in the pipette cone in the well containing the washing solution.

9. The method as claimed in claim 8, wherein the release of the captured particles comprises a phase of applying the cycles in such a way as to carry out an up and down movement of a meniscus of the solution over a pellet of particles captured in the pipette cone, the up and down movement of the meniscus being carried out on a portion of the cone less than the total length of the pipette cone.

10. The method as claimed in claim 9, wherein the release of the captured particles comprises a second phase of applying the cycles so as to totally suction and discharge the cone washing solution.

11. The method as claimed in claim 10, wherein the frequency of application of the cycles of the second phase is lower than the frequency of application of the cycles of the first phase.

12. The method as claimed in claim 8, wherein, prior to the release of the captured particles, at least two washing phases are carried out in two distinct washing solutions.

13. The method as claimed in claim 8, wherein the components contained in the biological sample are nucleic acids.

14. The method as claimed in claim 1, wherein the components contained in the biological sample are microorganisms, and wherein the method comprises a single capturing phase and a single washing phase.

15. The method as claimed in claim 14, wherein the mixture of the sample with the magnetic particles has a volume of greater of 1 milliliter, and wherein the volume of the recovery well is less than 200 microliters.

16. The method as claimed in claim 1, comprising, prior to the transferring phase, at least one phase of washing the particles captured on the internal wall of the pipette cone:

by suctioning the washing solution in the pipette cone;

then by modulating the first magnetic field applied to the magnetic particles in order to capture the particles on the internal wall of the pipette cone;

then by discharging the pipette cone washing liquid.

17. The method as claimed in claim 16, wherein the modulation of the first magnetic field is carried out:

by moving the pipette cone parallel to a longitudinal axis of the cone, and by keeping the first magnetic field constant;

and/or by passing magnets spaced out from one another in front of the captured particles.

18. The method as claimed in claim 1, wherein the volume of the pipette cone is at least ten times greater than the volume of the recovery well.

19. The method as claimed in claim 1, wherein the volume of the mixture is at least three times greater than the volume of the pipette cone.

20. The method as claimed in claim 1, wherein the components belong to the group formed by nucleic acids, microorganisms, proteins, and peptides.

21. A pipette holder comprising:

a base;

a recess made in the base, which can removably house a well support;

a pipette support comprising a first housing into which can be inserted a pipette equipped with at least one tubular pipette cone comprising a tip intended for pipetting liquid, the first housing opening out onto the recess of the base, the pipette support being translationally mobile relative to the base in a direction parallel to an axis of the pipette cones and mobile between a first position in which the tip of each pipette cone is inserted in a well of the well support and at least one second position in which the tip is outside the well;

a second housing which can removably house a magnetized part, the second housing facing each of the pipette cones in a position above the tip thereof when the pipette support is in the first position, and the second housing facing the tip of the pipette cone when the pipette support is in the second position.

22. The pipette holder as claimed in claim 21, wherein the first housing comprises an opening for the frontal insertion of the pipette into and the frontal removal of the pipette from the first housing.

23. The pipette holder as claimed in claim 21, wherein the second housing is made in the base.

24. The pipette holder as claimed in claim 21, comprising a third housing in the pipette support into which the magnetized part can be removably inserted in order to face each pipette cone at a position above the tip of the cone when the pipette support is in the second position.

25. The pipette holder as claimed in claim 24, wherein the second and third housings communicate, and wherein the pipette support comprises means capable of removably maintaining the magnetized part in the third housing.

26. The pipette holder as claimed in claim 21, wherein:

the base comprises at least one toothed wheel which can rotate;

and the pipette support comprises a rack which engages with the toothed wheel in order to translationally move the pipette support relative to the base during the rotation of the toothed wheel.

27. The pipette holder as claimed in claim 26, comprising a device for locking and unlocking the pipette support at least in the first position.

28. The pipette holder as claimed in claim 26, comprising at least one handle rigidly connected to the toothed wheel for turning the wheel and capable of removably attaching to a handle rigidly connected to the toothed wheel of another pipette holder.

29. A system for extracting components contained in a biological sample in liquid form, the components being capable of binding to magnetic particles, the system comprising:

a pipette equipped with at least one tubular pipette cone comprising a tip intended for pipetting liquid and with a circuit for suction and discharge in each pipette cone;

at least one well support;

a pipette holder comprising;

a base;

a recess made in the base, which can removably house each well support;

a pipette support comprising a first housing into which the pipette is inserted, the first housing opening out onto the recess of the base, the pipette support being translationally mobile relative to the base in a direction parallel to an axis of the pipette cones and mobile between a first position in which the tip of each pipette cone is inserted in a well of the well support and at least one second position in which the tip is outside the well;

a second housing facing each of the pipette cones in a position above the tip thereof when the pipette support is in the first position, and the second housing facing the tip of the pipette cone when the pipette support is in the second position; and

a magnetized part removably inserted in the second housing.

30. (canceled)

31. A well support, comprising a part in which recesses for receiving the wells are made, and at least one magnet facing each of the recesses made in the part.