Patent US4920061A successfully refreshed from Google Patents.
US4920061A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biological magnetic colloids
Assignee: The University of Texas System
•
Filing: 1986-07-08
•
Granted: 1990-04-24
•
Expires: 2006-07-08
Abstract
Abstract Colloidal-sized paramagnetic particles are formed with affinity ligands directly adsorbed to their surface. The colloidal-sized particles can form a colloidal disperse phase which is distributed through an aqueous dispersion medium to form a biological magnetic fluid. The fluid can be used to selectively separate cells from a cell mixture.
Inventors
- 👤 Christopher H. Poynton
- 👤 Christopher L. Reading
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:01
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/48; A61K9/50; A61K9/5094; A61M; A61M1/00; A61M1/36; A61M1/3618; B; B03; B03C; B03C1/00; B03C1/005; B03C1/01; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/53; G01N33/543; G01N33/54313; G01N33/54326; G01N33/5434; G01N2333/00; G01N2333/435; G01N2333/76; G01N2446/00; G01N2446/20; G01N2446/30; G01N2446/80; G01N2446/84
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
38 words
A colloidal biological magnetic fluid comprising a colloidal dispersed phase further comprising colloidal-sized substantially spherical paramagnetic cobalt particles coated with affinity ligands directly adsorbed to the particle surface, said colloidal dispersed phase distributed through an aqueous dispersion medium.
Claim 2
Dependent Claim
38 words
A colloidal biological magnetic fluid comprising a colloidal dispersed phase further comprising colloidal-sized substantially spherical paramagnetic cobalt particles coated with affinity ligands directly adsorbed to the particle surface, said colloidal dispersed phase distributed through an aqueous dispersion medium.
Claim 3
Dependent Claim
16 words
The biological magnetic fluid of claim 1 wherein said affinity ligands are avidin, lectins or immunoglobulins.
Claim 4
Dependent Claim
21 words
The biological magnetic fluid of claim 1 wherein said colloidal dispersed phase is passivated to inhibit reoxidation of said cobalt particles.
Claim 5
Dependent Claim
16 words
The biological magnetic fluid of claim 3 wherein said colloidal dispersed phase is passivated with dichromate.
Claim 6
Dependent Claim
14 words
The biological magnetic fluid of claim 1 wherein said colloidal dispersed phase is stabilized.
Claim 7
Dependent Claim
18 words
The biological magnetic fluid of claim 5 wherein said colloidal dispersed phase is stabilized with human serum albumin.
Claim 8
Independent Claim
51 words
A method of making a colloidal biological magnetic fluid comprising: (a) reducing a complexed aqueous solution of a cobalt salt with a reducing agent to form an aqueous colloidal suspension of cobalt; (b) adding an aqueous solution of affinity ligands; (c) stabilizing said colloidal suspension; and (d) passivating said colloidal suspension.
Claim 9
Independent Claim
51 words
A method of making a colloidal biological magnetic fluid comprising: (a) reducing a complexed aqueous solution of a cobalt salt with a reducing agent to form an aqueous colloidal suspension of cobalt; (b) adding an aqueous solution of affinity ligands; (c) stabilizing said colloidal suspension; and (d) passivating said colloidal suspension.
Claim 10
Dependent Claim
62 words
The method of claim 7 wherein said reduction of complexed aqueous solution of cobalt salt is accomplished in two stages comprising: (a) reducing a first portion of said complexed aqueous solution of cobalt salt with a reducing agent to form an initial aqueous colloidal suspension; then (b) reducing the remainder of said complexed aqueous solution of cobalt salt with said reducing agent.
Claim 11
Dependent Claim
20 words
The method of claim 7 further comprising ultrafiltering said stabilized and passivated colloidal magnetic fluid to concentrate said colloidal suspension.
Claim 12
Dependent Claim
14 words
The method of claim 9 further comprising separating unbound affinity ligands by gel filtration.
Claim 13
Dependent Claim
13 words
The method of claim 10 further comprising sterilizing said colloidal suspension by filtration.
Claim 14
Dependent Claim
17 words
The method of claim 7 further comprising adding human serum albumin and then lyophilizing the magnetic liquid.
Claim 15
Dependent Claim
25 words
A fluid, comprising an aqueous colloidal suspension of substantially spherical paramagnetic cobalt particles coated with affinity ligands adsorbed directly to the surface of the particle.
Claim 16
Dependent Claim
25 words
A fluid, comprising an aqueous colloidal suspension of substantially spherical paramagnetic cobalt particles coated with affinity ligands adsorbed directly to the surface of the particle.
Claim 17
Dependent Claim
14 words
The fluid of claim 13 wherein the affinity ligands are avidin, lectins or immunoglobulins.
Claim 18
Dependent Claim
20 words
The fluid of claim 13 wherein the cobalt particles range in size from at least about 30 nanometers in diameter.
References Cited (Backward Citations)
US29474A
Cited
USRE29474E
Cited
US3796634A
Cited
US4096316A
Cited
US3970518A
Cited
FR2334106A1
Cited
US4158547A
Cited
US4115534A
Cited
US4267234A
Cited
US4219335A
Cited
US4228237A
Cited
US4335094A
Cited
FR2463807A1
Cited
WO1983000106A1
Cited
US4454234A
Cited
US4687748A
Cited
US4452773A
Cited
US4477576A
Cited
US4550086A
Cited
US4582810A
Cited
US4735796A
Cited
GB2152664A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-23 | 1993-10-23 | 1994-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-23 | 1997-10-23 | 1998-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-23 | 2001-10-23 | 2002-04-24 | $7700.00 | Window Closed / Lapsed |