Method for manipulating magnetic particles in a liquid medium

摘要

The invention relates to a method of handling and mixing magnetic particles within a reaction chamber that is part of a microfluidic device and that contains the said particles in suspension. More particularly, the invention concerns a method of handling magnetic particles in a way to improve the mixing of the particles with the surrounding liquids medium and where the liquid is carried by a fluid flow as part of an automated system. Further, the invention describes the use of the method for conducting biological and chemical assays.

主权项

1. A method of mixing magnetic particles with a reagent in a reaction chamber that is part of a microfluidic device and that contains the particles in suspension, comprises the steps:
a. providing an electromagnetic means to generate magnetic field sequences having polarity and intensity that vary in time and a magnetic field gradient that covers the whole space of the reaction chamber; b. applying a first magnetic field sequence to separate or confine the particles so the particles occupy a sub-volume in the volume of the reaction chamber; c. injecting a defined volume of the said reagent in the reaction chamber; d. applying a second magnetic field sequence having polarity and amplitude that vary in time to induce continuous time variations of the position of the magnetic field gradient maxima across the reaction chamber thereby causing the particles in use to be in relative translation and rotational motion as a fog of particles covering substantially the whole reaction chamber volume; e. leaving the fog of particles in a homogenous state for a defined period of time to allow a reaction to take place between the particle surfaces and the reagent injected in the said reaction chamber, thereby forming a complex; and f. repeating the steps (b)-(e) until a given reagent volume has passed through the reaction chamber.