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US4452773A
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Magnetic iron-dextran microspheres
Assignee: University of British Columbia
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Filing: 1982-04-05
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Granted: 1984-06-05
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Expires: 2002-04-05
Abstract
Abstract The invention relates to colloidal sized particles composed of magnetic iron oxide (Fe3O4) coated with a polysaccharide, preferably dextran, or a derivative thereof having pendant functional groups. The particles have a magnetic moment, are electron dense, and are stable and non-aggregating under physiological conditions. They can be covalently bonded to antibodies, enzymes and other biological molecules and used to label and separate cells, cellular membranes and other biological particles and molecules by means of a magnetic field.
Inventors
- 👤 Robert S. Molday
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:24
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28002; B01J20/28009; A; A61; A61K; A61K51/00; A61K51/12; A61K51/1241; A61K51/1244; A61K51/1251; B01D; B01D15/00; B01D15/08; B01D15/26; B01D15/38; B01D15/3804; B01D15/3809; B01J20/30; B01J20/32; B01J20/3202; B01J20/3204; B01J20/3231; B01J20/3242; B01J20/3268; B01J20/3272; B01J20/3274; B01J20/328; B01J20/3291; B01J20/3293; B03; B03C; B03C1/00; B03C1/005; B03C1/01; C; C02; C02F; C02F1/00; C02F1/48; C02F1/488; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/53; G01N33/543; G01N33/54313; G01N33/54326; G01N33/5434; H; H01; H01F; H01F1/00; H01F1/44; H01F1/445; A61K2123/00; G01N2400/00; G01N2400/10; G01N2400/12; G01N2400/14; G01N2400/22; G01N2446/00; G01N2446/20; G01N2446/30; G01N2446/80; G01N2446/86
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
30 words
Discrete colloidal sized particles having a core of ferromagnetic iron oxide (Fe 3 O 4 ) and coated with a water-soluble polysaccharide or a derivative thereof having pendant functional groups.
Claim 2
Dependent Claim
30 words
Discrete colloidal sized particles having a core of ferromagnetic iron oxide (Fe 3 O 4 ) and coated with a water-soluble polysaccharide or a derivative thereof having pendant functional groups.
Claim 3
Dependent Claim
16 words
Particles as claimed in claim 1 having a diameter of about 100 to about 700 Å.
Claim 4
Dependent Claim
16 words
Particles as claimed in claim 1 having a diameter of about 300 to about 400 Å.
Claim 5
Dependent Claim
11 words
Particles as claimed in claim 1 wherein the polysaccharide is dextran.
Claim 6
Dependent Claim
12 words
Particles as claimed in claim 1 which have pendant aldehyde functional groups.
Claim 7
Dependent Claim
12 words
Particles as claimed in claim 1 which have pendant amino functional groups.
Claim 8
Dependent Claim
27 words
Particles as claimed in claim 1, 5 or 6 to which are attached biological molecules or particles bonded to functional groups of the polysaccharide or polysaccharide derivative.
Claim 9
Dependent Claim
24 words
Particles as claimed in claim 1 or 5 to which are attached a protein bonded to functional groups of the polysaccharide or polysaccharide derivative.
Claim 10
Dependent Claim
19 words
Particles as claimed in claim 5 to whose aldehyde functional groups is attached the protein S. Aureus Protein A.
Claim 11
Dependent Claim
14 words
Particles as claimed in claim 5 to whose aldehyde functional groups is attached immunoglobulin.
Claim 12
Dependent Claim
32 words
Particles as claimed in claim 1, 5 or 6 to which are attached biological molecules or particles selected from the group consisting of antibodies, cells, enzymes, drugs, toxins, hormones and nucleic acids.
Claim 13
Dependent Claim
32 words
Particles as claimed in claim 9 or 10 wherein there are attached to the protein biological particles selected from the group consisting of antibodies, cells, enzymes, drugs, toxins, hormones and nucleic acids.
Claim 14
Dependent Claim
50 words
A process for preparing colloidal sized particles as claimed in claim 1 which comprises mixing a water-soluble polysaccharide or a derivative thereof having pendant functional groups with an aqueous solution containing ferrous and ferric salts, adding alkali to the solution and separating polysaccharide- or polysaccharide derivative-coated ferromagnetic iron oxide particles.
Claim 15
Dependent Claim
17 words
A process according to claim 13 wherein the ferrous and ferric salts are ferrous and ferric chlorides.
Claim 16
Dependent Claim
36 words
A process according to claim 13 wherein aqueous ammonium hydroxide is added dropwise to the solution of ferrous and ferric salts to raise the pH to a value in the range of from 10 to 11.
Claim 17
Dependent Claim
23 words
A process according to claim 10 wherein the polysaccharide is dextran having an average molecular weight of between about 10,000 and about 70,000.
Claim 18
Dependent Claim
41 words
A process according to claim 13 wherein a polysaccharide at least some of whose hydroxyl groups have been oxidized to aldehyde group is mixed with the aqueous solution of ferrous and ferric salts, to obtain particles having pendant aldehyde functional groups.
Claim 19
Dependent Claim
39 words
A process according to claim 10 wherein a polysaccharide is mixed with the aqueous solution of ferrous and ferric salts and the process comprises the further step of oxidizing the polysaccharide coated particles to form pendant aldehyde functional groups.
Claim 20
Dependent Claim
52 words
A process according to claim 13 which comprises the further step of reacting a polysaccharide coated particle having pendant aldehyde functional groups with an amino-group containing molecule to form a Schiff base and then reducing the Schiff base so that the amino-group containing molecule is stably attached to the polysaccharide coated particle.
Claim 21
Dependent Claim
14 words
A process according to claim 19 wherein the amino-group containing molecule is a protein.
Claim 22
Dependent Claim
14 words
A process according to claim 20 wherein the protein is S. Aureus Protein A.
Claim 23
Dependent Claim
11 words
A process according to claim 20 wherein the protein is immunoglobulin.
Claim 24
Dependent Claim
49 words
A process according to claim 19 wherein the amino-group containing molecule is an α,ω-alkylene diamine and the process comprises the further step of reacting the obtained polysaccharide coated particles having pendant amino functional groups with an α,ω-dialdehyde, followed by reduction to obtain polysaccharide coated particles having pendant aldehyde groups.
Claim 25
Dependent Claim
48 words
A process according to claim 19 wherein the amino-group containing molecule is diaminoethane or diaminoheptane and the process comprises the further step of reacting the obtained polysaccharide coated particles having pendant amino functional groups with glutaraldehyde, followed by reduction to obtain polysaccharide coated particles having pendant aldehyde groups.
Claim 26
Dependent Claim
33 words
A process according to claim 13 which comprises the further step of reacting the product with biological particles selected from the group consisting of antibodies, cells, enzymes, drugs, toxins, hormones and nucleic acids.
Claim 27
Independent Claim
78 words
A method of separating a required antigen from a population of antigens which comprises introducing into the population of antigens discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide or a derivative thereof to which is attached an antibody specific to the required antigen, so that there are formed antigen-antibody conjugates on the particles, separating the particles by magnetic means and subsequently dissociating the antigen-antibody conjugate, to obtain the required antigen.
Claim 28
Independent Claim
78 words
A method of separating a required antigen from a population of antigens which comprises introducing into the population of antigens discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide or a derivative thereof to which is attached an antibody specific to the required antigen, so that there are formed antigen-antibody conjugates on the particles, separating the particles by magnetic means and subsequently dissociating the antigen-antibody conjugate, to obtain the required antigen.
Claim 29
Dependent Claim
30 words
A method according to claim 26 wherein the antigen-antibody conjugate is dissociated by reaction with sodium thiocyanate, by reaction with urea, by acidification or by digestion with a proteolytic enzyme.
Claim 30
Independent Claim
56 words
A method of treating a tumour which comprises introducing into the patient having the tumor a cytotoxic drug attached to discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide and applying an external magnetic field to localize the particles bearing the cytotoxic drug in the region of the tumour.
Claim 31
Independent Claim
56 words
A method of treating a tumour which comprises introducing into the patient having the tumor a cytotoxic drug attached to discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide and applying an external magnetic field to localize the particles bearing the cytotoxic drug in the region of the tumour.
Claim 32
Independent Claim
60 words
A method of labeling cells, enzymes, toxins, hormones, lectins, growth factors, nucleic acids or radiosotopes, discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide or a derivative thereof having pendant functional groups, the particles being attached to the cells, enzymes, toxins, hormones, lectins, growth factors, nucleic acids or radioisotopes via the functional group.
Claim 33
Independent Claim
60 words
A method of labeling cells, enzymes, toxins, hormones, lectins, growth factors, nucleic acids or radiosotopes, discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide or a derivative thereof having pendant functional groups, the particles being attached to the cells, enzymes, toxins, hormones, lectins, growth factors, nucleic acids or radioisotopes via the functional group.
Claim 34
Dependent Claim
36 words
A method according to claim 29 which comprises the further step of separating labeled cells, enzymes, toxins, hormones, lectins, growth factors, nucleic acids or radioisotopes attached to the particles of ferromagnetic iron oxide by magnetic means.
Claim 35
Independent Claim
62 words
A method of cleaning water contaminated with an undesirable chemical agent which comprises adding to the water discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide or a derivative thereof having pendant functional groups to which is attached a proteolytic enzyme which will digest the undesirable chemical agent, and recovering the particles by magnetic means.
Claim 36
Independent Claim
62 words
A method of cleaning water contaminated with an undesirable chemical agent which comprises adding to the water discrete colloidal sized particles having a core of ferromagnetic iron oxide and coated with a polysaccharide or a derivative thereof having pendant functional groups to which is attached a proteolytic enzyme which will digest the undesirable chemical agent, and recovering the particles by magnetic means.
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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) | 1987-06-05 | 1987-12-05 | 1988-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-05 | 1991-12-05 | 1992-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-05 | 1995-12-05 | 1996-06-05 | $7700.00 | Window Closed / Lapsed |