Method for processing a biological sample with magnetic particles

Patent metadata

Field	Value
Publication number	US-12036552-B2
Application number	US-202016895533-A
Country	US
Kind code	B2
Filing date	Jun 8, 2020
Priority date	Oct 11, 2017
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

The present disclosure relates to a method for isolating a biological target material from a liquid sample in a multiwell plate using magnetic particles, wherein high efficiency and low elution volumes are achieved by specific movements of the multiwell plate and a magnetic separation plate in relation to each other. Also disclosed is a pre-analytical system suitable for carrying out the method.

First claim

The invention claimed is:

1. A method for isolating a biological target material from a liquid sample, the method comprising the steps of:
a. providing a multiwell plate having a plurality of wells each having an open top and a closed bottom, wherein at least a first well of the plurality of wells comprises the liquid sample and magnetic particles having a binding surface, the multiwell plate further comprising recesses in positions corresponding to a predetermined geometrical arrangement of a plurality of magnets of a magnetic separation plate;
b. incubating the liquid sample and the magnetic particles in the at least the first well under conditions in which the biological target material binds to the binding surface of the magnetic particles, wherein the incubation is performed in an incubation position of the multiwell plate and the magnetic separation plate, where in the incubation position the multiwell plate and the magnetic separation plate are distanced from each other such that the magnets of the magnetic separation plate do not impose a magnetic field gradient within the wells of the multiwell plate to move the magnetic particles;
c. introducing the magnets of the magnetic separation plate into the recesses of the multiwell plate to an upper peripheral collection position such that when the magnets are positioned in the upper peripheral collection position a magnetic field gradient may be imposed on an inner space of each well of the plurality of wells, thereby forming a pellet of magnetic particles along an inner wall of the at least the first well, wherein the pellet is positioned at a first specific height along the inner wall of the at least the first well;
d. moving the multiwell plate and/or the magnetic separation plate relatively to each other to a lower peripheral collection position, wherein the relative movement of the multiwell plate and/or the magnetic separation plate to the lower peripheral collection position comprises both vertical and lateral movement components such that the formed pellet is slid along the inner wall of the at least the first well in a direction substantially from top to bottom by the magnetic field gradient to reach a second specific height along the inner wall of the at least the first well, wherein the second specific height is a height between the first specific height and a bottom of the at least the first well;
e. introducing a pipette tip of a pipettor into the at least the first well of the plurality of wells of the multiwell plate and down into sufficient proximity to the bottom of the at least the first well to withdraw the maximum possible amount of liquid with the pipette tip, wherein the lateral positions of the pellet and the pipette tip are spaced apart sufficiently for the pellet of magnetic particles and the pipette tip to avoid a physical interaction between one another sufficient to disturb the pellet;
f. withdrawing the liquid from the at least the first well while retaining the formed pellet against the inner wall at the second specific height by magnetic force;
g. optionally adding a washing buffer to the at least the first well of the plurality of wells for removing undesired components from the surface of the magnetic particles while retaining the biological target material thereon, then withdrawing the liquid from the at least the first well of the plurality of wells while retaining the formed pellet against the inner wall of the at least the first well at the second specific height by magnetic force;
h. moving the magnets of the magnetic separation plate from the recesses in the multiwell plate to the incubation position of multiwell plate and magnetic separation plate, and adding an elution buffer to the at least the first well of the plurality wells resulting in a second liquid volume in the at least the first well, wherein the second liquid volume is smaller than the first liquid volume, and resuspending the magnetic particles therein;
i. eluting the biological target material from the magnetic particles with the elution buffer;
j. introducing the magnets of the magnetic separation plate into the recesses of the multiwell plate to reach the lower peripheral collection position, wherein each magnet is in sufficient proximity to the outside wall of a corresponding well to impose a magnetic field gradient on the inner space of the at least the first well, thereby forming a pellet of magnetic particles at the inner wall of the at least the first well at the second specific height;
k. introducing the pipette tip of the pipettor into the at least the first well of the plurality of wells of the multiwell plate down into sufficient proximity to the bottom of the at least the first well of the plurality of wells to withdraw the maximum possible amount of liquid with the pipette tip, wherein the lateral positions of the pellet and the pipette tip are spaced apart sufficiently for the pellet and the pipette tip to avoid a physical interaction between one another sufficient to disturb the pellet;
l. Withdrawing the eluate including the isolated biological target material from the at least the first well of the plurality of wells while retaining the pellet of magnetic particles by magnetic force,

wherein at least a first magnet is moved toward the at least the first well of the plurality of wells and wherein at least a second magnet is moved away from the at least the first well of the plurality of wells during the lateral movement component of step (d).

2. The method of claim 1 , wherein the magnetic particles have a mean diameter from 50 nm to 50 μm.

3. The method of claim 1 , wherein the magnetic particles are superparamagnetic.

4. The method of claim 1 , wherein the elution volume in step h. is from 5 μl to 50 μl.

5. The method of claim 1 , wherein the lateral movement of the multiwell plate and/or the magnetic separation plate relative to each other is one-dimensional along a horizontal axis.

6. The method of claim 1 , wherein the vertical and lateral movement of the multiwell plate and/or the magnetic separation plate relative to each other is guided by a guiding screen having guiding rails, the guiding screen being essentially perpendicular to the multiwell plate and/or to the magnetic separation plate.

7. A method for isolating a biological target material from a liquid sample, the method comprising the steps of:
a. providing a multiwell plate having a plurality of wells with an open top and a closed bottom, wherein at least a first well of the plurality of wells comprises the liquid sample and magnetic particles having a binding surface, the multiwell plate further comprising recesses in positions corresponding to a predetermined geometrical arrangement of a plurality of magnets of a magnetic separation plate;
b. incubating the liquid sample and the magnetic particles in the at least the first well under conditions in which the biological target material binds to the binding surface of the magnetic particles, wherein the incubation is performed in an incubation position of the multiwell plate and magnetic separation plate, where in the incubation position the multiwell plate and the magnetic separate plate are distanced from each other such that the magnets of the magnetic separation plate do not impose a magnetic field gradient within the wells of the multiwell plate to move the magnetic particles;
c. introducing the magnets of the magnetic separation plate into the recesses of the multiwell plate to an upper peripheral collection position such that when the magnets are positioned in the upper peripheral collection position a magnetic field gradient may be imposed on an inner space of the at least the first well, thereby forming one or more pellets of magnetic particles along an inner wall of the at leas

Assignees

• Roche Molecular Systems Inc

Inventors

• Korner Stephan
• Sarofim Emad
• Savatic Goran
• Simic Marko

Classifications

• B03C2201/26

  for use in medical or biological applications · CPC title

• B03C2201/18

  Magnetic separation whereby the particles are suspended in a liquid · CPC title

• B03C1/28

  Magnetic plugs and dipsticks · CPC title

• B01L2300/0829

  Multi-well plates; Microtitration plates · CPC title

• B01L2200/0668

  Trapping microscopic beads · CPC title