Method and apparatus for magnetically separating selected particles, particularly biological cells

Abstract

A method and apparatus for magnetically separating target particles of a selected type from a sample in order to produce a concentration of the target particles in the sample, or a depletion of the sample with respect to the target particles, by producing a sample mixture of the sample with magnetic particles having a selective affinity to magnetically stain the target particles; producing a flow of a buffer liquid through a tube which includes an inlet connectable to a source of buffer liquid, and an outlet for the buffer liquid; after a flow of the buffer liquid has been produced through the tube, introducing the sample mixture into the buffer liquid flowing through the tube such that the buffer liquid forms a continuous liquid carrier for the sample mixture as both are fed through the tube; and applying a magnetic field across the tube at a magnetizing station therein to cause the magnetically-stained target particles to be separated and retained in the buffer liquid within the tube at the magnetizing station.

Description

FIELD AND BACKGROUND OF THE INVENTION[0001] The present invention relates to a method and apparatus for magnetically separating particles of a selected type (hereinafter called "target particles") from a sample in order to produce a concentration of the target particles in the sample, and or a depletion of the sample with respect to the target particles. The invention is particularly useful for magnetically separating biological cells of a selected type, e.g., a selected type of lymphocyte cell in a blood sample, and is therefore described below especially with respect to such applications.[0002] A large number of applications involving the magnetic separation of biological cells are described in the literature, for example in U.S. Pat. No. 4,710,472 and the many publications cited therein, which are hereby incorporated by reference. Many such applications require not only the separation of one or more specific types of cells (hereinafter called "target cells"), but also the mainten...

AI Technical Summary

Benefits of technology

[0004] An object of the present invention is to provide a method of magnetically separating target particles of a selected type from a sample in a manner which causes less damage to the membrane than the above described known technique. Another object of the present invention is to provide apparatus for magnetically separating target particles in accordance with the novel method.

[0005] According to one aspect of the present invention, there is provided a method of magnetically separating target particles of a selected type from a sample in order to produce a concentration of the target particles in the sample, or a depletion of the sample with respect to the target particles, comprising: producing a sample mixture of the sample with magnetic particles having a selective affinity to magnetically stain the target particles; feeding a buffer liquid through a tube which includes an inlet connectable to a source of buffer liquid, and an outlet for the buffer liquid; introducing the sample mixture into the buffer liquid such that the buffer liquid forms a continuous liquid carrier for the sample mixture as both are fed through the tube; and applying a magnetic field across the tube at a magnetizing station therein to cause the magnetically-stained target particles to be separated and retained in the buffer liquid within the tube at the magnetizing station.

[0010] Such a method and apparatus have been found to enable the separation of selected types of particles, (target particles), particularly biological cells (target cells), without causing undue damage to either the target particles or the untargetted particles. Thus, the buffer liquid, which forms a continuous liquid carrier for both the target particles and the untargetted particles, produces a constant liquid volume which physically supports both types of particles (or cells) during both phases of the process, thereby minimizing damage to both types of particles during both phases.

Problems solved by technology

In this known process, however, it was found that the membranes of the cells are excessively damaged by the liquid-pervious magnetic body, which reduces the effectiveness of the technique for research or clinical purposes.

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