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 proton 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 hold the receptacle device in a fixed position with respect to the receptacle carrier;
a fluid transfer device comprising a plurality of aspirator probes aligned in a side-by-side arrangement and including a probe moving mechanism to move the plurality of probes in unison with respect to the receptacle carrier, wherein the multiple receptacles of the receptacle device carried in the receptacle carrier are positioned so as to be operatively engageable by the aspirator probes;
wherein the receptacle carrier includes an orbital mixer assembly configured to impart orbital motion to a receptacle device carried by the receptacle carrier and 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; and
a magnet moving apparatus including at least one magnet generating a magnetic field, said magnet moving apparatus including a drive system configured to effect linear translation of said 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; and
an instrument control module in communication with the orbital mixer assembly, the probe moving mechanism, and magnet moving apparatus drive system and configured to:
activate the receptacle carrier orbital mixer assembly to move the receptacle device to the second position and activate the magnet moving apparatus drive system to move the at least one magnet to the operational position 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 of the multiple receptacles of the receptacle device adjacent to the at least one magnet wherein the effect of the magnetic field on the magnetically-responsive solid supports is less when the at least one magnetic is in the non-operational position than when the at least one magnetic is in the operational position, and
activate the receptacle carrier orbital mixer assembly to move the receptacle device to the first position with respect to the fluid transfer device, so that at least one of the multiple receptacles of the receptacle device interferes with translation of the magnet by the magnet moving apparatus drive system from the non-operational position to the operational position.
2. The apparatus of claim 1 , 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 2 , wherein the magnet moving apparatus comprises a plurality of stripping elements, 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,
wherein when the magnet moving apparatus is in a position corresponding to the operational position of at least one magnet, and no receptacle device is carried in the receptacle carrier, each stripping element is in a position to engage the associated aspirator probe to strip the conduit mounted thereon, and when said magnet moving apparatus is in a position corresponding to the non-operational position of the at least one magnet, no stripping element is in a position to engage the associated aspirator probe to strip the conduit mounted thereon.
4. 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.
5. 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 coupled 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.