US5458785A
Expired / Lapsed
US
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Magnetic separation method
Assignee: GE Healthcare Ltd
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Filing: 1993-09-24
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Granted: 1995-10-17
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Expires: 2013-09-24
Abstract
Abstract Biological assay systems often involve suspending magnetically attractable particles in a liquid, and later bringing down the particles from suspension and separating the formed pellet from the supernatant liquid. The invention provides magnetic systems for this purpose, shaped to form an annular or part-annular pellet close to the bottom of the vessel. The systems are suitable for automation.
Inventors
- 👤 Roland P. Howe
- 👤 Michael A. Reeve
- 👤 Daniel Bischof
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:58
CPC Classifications
B; B03; B03C; B03C1/00; B03C1/02; B03C1/035; B03C1/025; B03C1/031; B03C1/033; B03C1/0332; B03C1/0335; B03C1/28; B03C1/288; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/53; G01N33/543; G01N33/54313; G01N33/54326; B03C2201/00; B03C2201/26; G01N35/00; G01N35/0098; Y; Y10; Y10T; Y10T436/00; Y10T436/25; Y10T436/25375; Y10T436/255
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
138 words
A magnet system comprising: a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbor, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of nonmagnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a vessel at the work station.
Claim 2
Dependent Claim
138 words
A magnet system comprising: a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbor, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of nonmagnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a vessel at the work station.
Claim 3
Dependent Claim
246 words
A magnetic separation method which comprises the steps of: a) bringing a vessel having a bottom end and containing a liquid suspension of magnetically attractable particles into proximity with a magnet system whereby there is formed an annular or part-annular pellet comprising the magnetically attractable particles close to, but not at, the bottom end of the vessel; b) removing supernatant liquid from the vessel; and c) adding fresh liquid to the vessel; d) using the magnet system to draw the magnetically attractable particles to the bottom of the vessel; e) removing the magnet system; f) and re-suspending the magnetically attractable particles in the fresh liquid; g) wherein the magnet system comprises a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbors, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of non-magnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a said vessel at the work station.
Claim 4
Dependent Claim
246 words
A magnetic separation method which comprises the steps of: a) bringing a vessel having a bottom end and containing a liquid suspension of magnetically attractable particles into proximity with a magnet system whereby there is formed an annular or part-annular pellet comprising the magnetically attractable particles close to, but not at, the bottom end of the vessel; b) removing supernatant liquid from the vessel; and c) adding fresh liquid to the vessel; d) using the magnet system to draw the magnetically attractable particles to the bottom of the vessel; e) removing the magnet system; f) and re-suspending the magnetically attractable particles in the fresh liquid; g) wherein the magnet system comprises a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbors, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of non-magnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a said vessel at the work station.
Claim 5
Dependent Claim
26 words
The method as claimed in claim 2, wherein during step c) sufficient fresh liquid is added to the vessel to submerge the annular or part-annular pellet.
Claim 6
Dependent Claim
16 words
The method as claimed in claim 2, wherein the vessel is a round-bottom or conical-bottom vessel.
Claim 7
Independent Claim
301 words
A method of treating a solution of a polymer in a vessel having a bottom end, by the use of magnetically attractable particles which do not specifically bind the polymer, comprising the steps of: a) suspending the magnetically attractable particles in the solution so as to form a liquid suspension of the magnetically attractable particles; b) precipitating the polymer out of solution whereby it becomes non-specifically associated with the magnetically attractable particles; c) bringing the vessel into proximity with a magnet system whereby there is formed an annular or part-annular pellet comprising the magnetically attractable particles and the precipitated polymer, said pellet being positioned close to, but not at, the bottom of the vessel; d) removing a supernatant liquid from the vessel; e) adding fresh liquid to the vessel; f) using the magnet system to draw the magnetically attractable particles to the bottom of the vessel; g) removing the magnet system; h) redissolving the polymer in the fresh liquid; and k) wherein the magnet system comprises a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbors, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of non-magnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a said vessel at the work station.
Claim 8
Independent Claim
301 words
A method of treating a solution of a polymer in a vessel having a bottom end, by the use of magnetically attractable particles which do not specifically bind the polymer, comprising the steps of: a) suspending the magnetically attractable particles in the solution so as to form a liquid suspension of the magnetically attractable particles; b) precipitating the polymer out of solution whereby it becomes non-specifically associated with the magnetically attractable particles; c) bringing the vessel into proximity with a magnet system whereby there is formed an annular or part-annular pellet comprising the magnetically attractable particles and the precipitated polymer, said pellet being positioned close to, but not at, the bottom of the vessel; d) removing a supernatant liquid from the vessel; e) adding fresh liquid to the vessel; f) using the magnet system to draw the magnetically attractable particles to the bottom of the vessel; g) removing the magnet system; h) redissolving the polymer in the fresh liquid; and k) wherein the magnet system comprises a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbors, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of non-magnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a said vessel at the work station.
Claim 9
Dependent Claim
14 words
The method as claimed in claim 5, wherein the polymer is a nucleic acid.
Claim 10
Dependent Claim
26 words
The method as claimed in claim 5, wherein during step e) sufficient fresh liquid is added to the vessel to submerge the annular or part-annular pellet.
Claim 11
Dependent Claim
16 words
The method as claimed in claim 5, wherein the vessel is a round-bottom or conical-bottom vessel.
Claim 12
Dependent Claim
246 words
Apparatus which comprises: an array of vessels each to contain a liquid suspension of magnetically attractable particles; a pipetting system for transferring liquid to and from the array of vessels; and a magnet system; and means for movably mounting the magnet system relative to the array of vessels, said means being adapted to bring the magnet system to any one of three positions and hold the magnet system in that position, the positions being: i) engaged with the array of vessels in an annular separation position; ii) engaged with the array of vessels in a pull-down separation position; and iii) free of the array of vessels; wherein the magnet system comprises: a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbors, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of non-magnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a said vessel at the work station.
Claim 13
Dependent Claim
246 words
Apparatus which comprises: an array of vessels each to contain a liquid suspension of magnetically attractable particles; a pipetting system for transferring liquid to and from the array of vessels; and a magnet system; and means for movably mounting the magnet system relative to the array of vessels, said means being adapted to bring the magnet system to any one of three positions and hold the magnet system in that position, the positions being: i) engaged with the array of vessels in an annular separation position; ii) engaged with the array of vessels in a pull-down separation position; and iii) free of the array of vessels; wherein the magnet system comprises: a carrier plate of non-magnetizable material; a back flow plate of magnetizable material overlying the carrier plate; a row of permanent magnets each having opposed first and second ends, the first end of each said magnet being positioned on the back flow plate with a N-S axis oriented perpendicular to the back flow plate, the polarity of each permanent magnet being opposite to that of its neighbor or neighbors, the permanent magnets being spaced apart to define between them one or more work stations; a field concentrator plate of magnetizable material overlying said second ends of the permanent magnets; and a cover plate of non-magnetizable material overlying the field concentrator plate; there being provided a hole through the field concentrator plate and the overlying cover plate for locating a said vessel at the work station.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-16 | 1999-04-17 | 1999-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-16 | 2003-04-17 | 2003-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-16 | 2007-04-17 | 2007-10-17 | $7700.00 | Window Closed / Lapsed |