Patent ID: 8870446

Claim:
A method of mixing magnetic particles designed to capture at least one target substance from a surrounding liquid medium, wherein said particles are contained in suspension within a reaction chamber that is a part a microfluidic network, wherein the reaction chamber comprises a narrow end and a large end that are connected to inlet and outlet ends for introducing and removing the liquid medium into and from the reaction chamber, and at least two electromagnetic poles face each other across the reaction chamber and retain the particles within the reaction chamber under fluid flow conditions, 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 and inhibit particle claim aggregates and to maintain the particles in suspension as a fog of particles in relative dynamic movement; and b) combining the magnetic fields from different magnetic poles in a sequence to induce continuous time variations of the position of the magnetic field gradient maxima across the reaction chamber, wherein the combination of steps a) and b) causes the particles in use to be in relative translational and rotational motion as a fog of particles homogeneously covering substantially the whole reaction chamber volume to allow an effective binding to take place between the particle surfaces and the sample in the reaction chamber, thereby forming a complex of the target substances and the magnetic particles.