FIELD OF THE INVENTION

The disclosure relates to a magnetic device for capturing and releasing magnetically susceptible particles.

BACKGROUND OF THE INVENTION

Devices for capturing and releasing magnetized, ferromagnetic, or superparamagnetic micro-particles are known. Generally, these devices include a movable magnet as well as either an extendable membrane, a shapeable membrane or a coating on the magnet.

What is needed is an improved device for capturing and releasing magnetically susceptible particles.

SUMMARY OF THE INVENTION

In one aspect of the present disclosure, a device for capturing and releasing magnetically susceptible particles comprises: a housing having a proximal end and a distal end; a retraction mechanism disposed within the housing; and a permanent, axially magnetized, cylindrical magnet disposed in the housing and coupled to the retraction mechanism, wherein a distal end of the magnet extends from the distal end of the housing, and wherein the retraction mechanism is configured to position the distal end of the magnet at one of a first, second or third predetermined distance from the distal end of the housing.

Another aspect of the present disclosure relates to a device for capturing and releasing magnetically susceptible particles that comprises: a housing having a proximal end and a distal end; a retraction mechanism, having a proximal end and a distal end, disposed within the housing; a planar structure disposed in the housing and coupled to the distal end of the retraction mechanism; and a plurality of permanent axially magnetized cylindrical magnets coupled to the planar structure, each magnet having a distal end extending from the distal end of the housing, wherein the retraction mechanism is configured to position the distal ends of the magnets at one of a first, second or third predetermined distance from the distal end of the housing.

In some embodiments with respect to these two aspects, the device further comprises a sleeve coupled to the distal end of the housing, wherein the sleeve is sized and arranged such that the magnet can move to the second predetermined distance without disturbing the coupling of the sleeve to the housing.

In some embodiments with respect to these two aspects, the device further comprises a ferromagnetic tube disposed over the magnet.

Yet another aspect of the present disclosure relates to a device for capturing and releasing magnetically susceptible particles comprises: a housing having a proximal end and a distal end; a displacement mechanism, having a proximal end and a distal end, disposed within the housing; a plurality of magnetic assemblies coupled to the housing, each magnetic assembly having a distal end extending from the distal end of the housing; a pusher plate coupled to the distal end of the displacement mechanism; a plurality of openings defined in the pusher plate, each opening configured and arranged to accommodate a respective magnetic assembly; and a plurality of sleeves, each sleeve disposed over a respective magnetic assembly and positioned adjacent the pusher plate, wherein each magnetic assembly comprises a cylindrical magnet disposed inside a ferromagnetic tube, and wherein the displacement mechanism is configured to move the pusher plate from a first position to a second position and back to the first position.

Advantageously, the device in accordance with aspects of the present disclosure has a retraction mechanism that allows for a single-handed, single digit, i.e., single finger, operation for placing a magnet in one of at least three different positions, including a protracted or retracted position for the capture and release, respectively, of magnetically susceptible particles, and a hyper-protracted position for the release of a disposable cover. The device allows the user to more easily move between the retracted and protracted positions to facilitate the movement of particles. In the hyper-protracted position, the magnet can eject the sleeve without the need for a separate ejection mechanism, thus simplifying the design. Further, the device eliminates the need to use a pipette or vacuum to remove liquid.

