Device and Method for Manipulating and Mixing Magnetic Particles in a Liquid Medium

• US 20130217144A1
• Filed: 01/23/2013
• Published: 08/22/2013
• Est. Priority Date: 06/21/2006
• Status: Active Grant

• Current Assignee: Spinomix SA
• Original Assignee: Spinomix SA
• Inventors: Rida, Amar
• Granted Patent: US 8,870,446 B2
• Time in Patent Office: Days
• US Class Current: 436/174
• 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: C12N 15/1013 by using magnetic beads
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• 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

Abstract

A device for manipulating and mixing magnetic particles (3) in a surrounding liquid medium, comprises at least one couple of magnetic poles (1,1′) facing each other across a gap, the facing poles diverging from a narrow end of the gap to a large end of the gap, the poles (1,1′) forming part of an electromagnetic circuit and being arranged to provide a magnetic field gradient in the gap region; and a reaction chamber (2) that is a part of a fluidic network for containing the said magnetic particles in suspension and placed in the gap of the said electromagnets poles (1,1′). The reaction chamber (2) preferably has at least one part which has a diverging cavity, arranged co-divergently in the diverging gap between the poles.

Claims

1. A method of mixing magnetic particles in a microfluidic environment with a surrounding medium in a reaction chamber that is a part a microfluidic network, wherein at least two electromagnetic poles face each other across the reaction chamber, the method comprising:

a) applying from the electromagnetic poles magnetic field sequences having polarity and intensity that vary in time;

said varying magnetic field sequences being effective to break an inhibit particle claim aggregates and to maintain the particles in suspension as a fog of particles in relative dynamic movement;

b) combining the magnetic fields from different magnetic poles in a sequence to induce displacement of the fog of particles across the reaction chamber whereby the fog of particles occupies substantially the whole reaction chamber volume.

2. The method according to claim 1, which further comprises the step of combining the magnetic fields from different magnetic poles in a sequence to separate or confine the particles so the particles occupy a sub-volume in the volume of the reaction chamber.

3. The method according to claim 1, wherein during the step (b) the particle size and the homogeneity of mixing the particles are controlled by varying respectively the frequency and the amplitude of the magnetic field.

4. The method of mixing particles according to claim 1, wherein the reaction chamber comprises at least one segment with diverging/converging parts, and at least one couple of electromagnetic poles face each other across the reaction chamber and geometrically arranged in a way to be co-diverging/co-converging with diverging/converging parts of the reaction chamber.

5. The method according to claim 4, wherein the magnetic poles form a quadrupole configuration.

6. The method of mixing magnetic particles with surrounding liquid according to claim 1, wherein the particles are designed to selectively bind the particle with at least one target molecule or with other particles carried in the reaction chamber by a fluid flow.

7. The method according to claim 1, wherein the fog of particles occupies substantially the whole reaction chamber volume quasi-instantaneously.

8. The method according to claim 1, wherein the fog of particles occupies substantially the whole reaction chamber volume over a period of time.