Method and apparatus for effecting automated movement of a magnet in an instrument for performing a magnetic separation procedure
View Patent ↗Methods, systems, and apparatus are provided for automated isolation of selected analytes, to which magnetically-responsive solid supports are bound, from other components of a sample. An apparatus for performing an automated magnetic separation procedure includes a mechanism for effecting linear movement of a magnet between operative and non-operative positions with respect to a receptacle device. A receptacle holding station within which a receptacle device may be temporarily stored prior to moving the receptacle to the apparatus for performing magnetic separation includes magnets for applying a magnetic field to the receptacle device held therein, thereby drawing at least a portion of the magnetically-responsive solid supports out of suspension before the receptacle device is moved to the magnetic separation station. An automated receptacle transport mechanism moves the receptacle devices between the apparatus for performing magnetic separation and the receptacle holding station.
1. An apparatus comprising:
a receptacle carrier configured to carry a receptacle device comprising multiple receptacles, each of the multiple receptacles having a wall and containing a solution which includes magnetically-responsive solid supports and to carry the receptacle device throughout a fluid transfer process;
a fluid transfer device comprising a plurality of aspirator probes aligned in a side-by-side arrangement, wherein the multiple receptacles of a receptacle device carried in the receptacle carrier are positioned so as to be operatively engageable by the aspirator probes, wherein the receptacle carrier is configured to selectively move the receptacle device between a first position with respect to the fluid transfer device and a second position with respect to the fluid transfer device, wherein the fluid transfer device further comprises a probe moving mechanism adapted to move the plurality of probes in unison with respect to the receptacle carrier, and wherein the probe moving mechanism and the receptacle carrier are configured so that movement of the plurality of probes with respect to the receptacle carrier when the receptacle carrier is in the first position will cause the distal end of each probe to engage an associated conduit carried on a receptacle device carried by the receptacle carrier so that a conduit becomes mounted on the distal end of each probe; and
a magnet moving apparatus including at least one magnet generating a magnetic field, the magnet moving apparatus being configured to effect linear translation of the at least one magnet in a direction transverse to the axes of the aspirator probes and parallel to the direction of aspirator probe alignment between an operational position with respect to the multiple receptacles of the receptacle device carried in the receptacle carrier and a non-operational position with respect to the multiple receptacles of the receptacle device carried in the receptacle carrier,
wherein the receptacle carrier and the magnet moving apparatus are configured so that the magnetic field of the at least one magnet draws the magnetically-responsive solid supports to an inner surface of the wall of each receptacle of the receptacle device adjacent to the at least one magnet when the at least one magnet is in the operational position, and wherein the effect of the magnetic field on the magnetically-responsive solid supports is less when the at least one magnet is in the non-operational position than when the at least one magnet is in the operational position,
wherein the receptacle carrier and the magnet moving apparatus are configured so that when the receptacle device is positioned in the first position with respect to the fluid transfer device, the receptacle device interferes with translation of the magnet by the magnet moving apparatus from the non-operational position to the operational position,
wherein the magnet moving apparatus comprises a plurality of stripping elements, and the magnet moving apparatus is configured to effect linear translation of the stripping elements when the magnet moving apparatus moves the at least one magnet between the operational position and the non-operational position, each stripping element being associated with a corresponding aspirator probe, and each stripping element being adapted to remove a conduit from the distal end of the associated aspirator probe, and
wherein when the magnet is in the operational position, each stripping element is in a position to engage the associated aspirator probe to strip the conduit mounted thereon, and when the magnet is in the non-operational position, no stripping element is in a position to engage the associated aspirator probe to strip the conduit mounted thereon.
2. The apparatus of claim 1 , wherein the fluid transfer device further comprises a probe moving mechanism adapted to move the plurality of probes in unison with respect to the receptacle carrier, and wherein the probe moving mechanism and the receptacle carrier are configured so that movement of the plurality of probes with respect to the receptacle carrier when the receptacle carrier is in the first position will cause the distal end of each probe to engage an associated conduit carried on a receptacle device carried by the receptacle carrier so that a conduit becomes mounted on the distal end of each probe.
3. The apparatus of claim 1 , wherein the magnet moving apparatus comprises:
a magnet carrier configured to carry the magnet;
a motor;
a threaded drive screw coupled to an output shaft of the motor; and
a screw follower mounted to the magnet carrier, wherein the drive screw is engaged with the screw follower such that powered rotation of the drive screw by the motor causes translation of the magnet carrier.
4. The apparatus of claim 1 , wherein the magnet moving apparatus comprises:
a magnet carrier configured to carry the magnet;
a motor with a drive pulley mounted to an output shaft thereof;
an idler pulley; and
a drive belt carried on the drive pulley and the idler pulley and attached to the magnet carrier to transfer powered rotation of the drive pulley to effect linear translation of the magnet carrier in a direction transverse to the axes of the aspirator probes.