Patent US1878413A successfully refreshed from Google Patents.
Patent US4090022A successfully refreshed from Google Patents.
US4090022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Porous cellulose beads
Assignee: Purdue Research Foundation
•
Filing: 1977-03-21
•
Granted: 1978-05-16
•
Expires: 1997-03-21
Abstract
Abstract Porous cellulose beads are prepared by distributing droplets of a solvent mixture containing a cellulose derivative into a precipitating solution to form porous beads which are then washed and hydrolyzed to form porous cellulose beads. The porous cellulose beads, which may be cross-linked, if desired, by suitable treatment, are useful carriers to which enzymes can be immobilized. The beads may also be used for the separation of enzymes, proteins, nucleic acids and the like, or to remove metal ions from dilute mining solutions.
Inventors
- 👤 George T. Tsao
- 👤 Li Fu Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:45
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; C12; C12N; C12N11/00; C12N11/02; C12N11/10; C12N11/12; C08J2201/00; C08J2201/04; C08J2201/054; C08J2201/0542; C08J2301/00; Y; Y10; Y10S; Y10S530/00; Y10S530/81; Y10S530/812; Y10S530/813; Y10S530/814
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
152 words
A process for the preparation of porous cellulose beads suitable for use as a carrier of enzymes and other biological agents which comprises the steps of: a. dissolving a hydrolyzable cellulose derivative in an inert organic, water-miscible solvent to form a solution having a density greater than that of a precipitation solution the cellulose derivative to solvent ratio ranging from 1:20 to 1:3 weight/volume; b. distributing said solution in the form of droplets into a precipitation solution whereby said cellulose derivative is precipitated in the form of uniformly porous beads; c. separating the precipitated beads from said solution; d. washing the separated porous beads with water; e. hydrolyzing the washed beads to convert the beads to cellulose and to increase the active sites for attachment of enzymes and other biological agents; f. washing the hydrolyzed beads to obtain porous cellulose beads having a uniformly distributed void space greater than 50% by volume.
Claim 2
Dependent Claim
152 words
A process for the preparation of porous cellulose beads suitable for use as a carrier of enzymes and other biological agents which comprises the steps of: a. dissolving a hydrolyzable cellulose derivative in an inert organic, water-miscible solvent to form a solution having a density greater than that of a precipitation solution the cellulose derivative to solvent ratio ranging from 1:20 to 1:3 weight/volume; b. distributing said solution in the form of droplets into a precipitation solution whereby said cellulose derivative is precipitated in the form of uniformly porous beads; c. separating the precipitated beads from said solution; d. washing the separated porous beads with water; e. hydrolyzing the washed beads to convert the beads to cellulose and to increase the active sites for attachment of enzymes and other biological agents; f. washing the hydrolyzed beads to obtain porous cellulose beads having a uniformly distributed void space greater than 50% by volume.
Claim 3
Dependent Claim
12 words
A process according to claim 1 wherein distributing is accomplished by spraying.
Claim 4
Dependent Claim
30 words
A process according to claim 1 wherein said precipitation solution is selected from the group consisting of water, hexane, cyclohexane, octane, benzene and mixtures of water and ethanol or methanol.
Claim 5
Dependent Claim
12 words
A process according to claim 3 wherein said precipitation solution is water.
Claim 6
Dependent Claim
22 words
A process according to claim 1 wherein said cellulose derivative is cellulose acetate and hydrolysis is carried out in a caustic solution.
Claim 7
Dependent Claim
80 words
A process according to claim 1 wherein said solvent is a mixture of: a. a member from the group consisting of acetone, a mixture of acetone and methanol or ethanol, methyl acetate, a mixture of methylene dichloride and methanol, methyl ethyl ketone, formamide and dimethyl sulfoxide; and b. a member from the group consisting of dimethyl sulfoxide, formamide, methyl acetate, cyclohexanone, methylene dichloride, ethylene dichloride, a mixture of methylene dichloride and methanol, and a mixture of ethylene dichloride and methanol.
Claim 8
Dependent Claim
16 words
A process according to claim 6 wherein said solvent is dimethyl sulfoxide, formamide or methyl acetate.
Claim 9
Dependent Claim
19 words
A process according to claim 1 wherein the void space of said beads is from about 75 to 95%.
Claim 10
Dependent Claim
25 words
A process according to claim 1 wherein said porous cellulose beads are cross-linked with at least one cross-linking agent to obtain cross-linked porous cellulose beads.
Claim 11
Dependent Claim
15 words
A process according to claim 9 wherein said beads are cross-linked prior to being hydrolyzed.
Claim 12
Dependent Claim
14 words
A process according to claim 9 wherein said beads are cross-linked after being hydrolyzed.
Claim 13
Dependent Claim
13 words
A process according to claim 9 wherein said cross-linking agent is a diisocyanate.
Claim 14
Dependent Claim
14 words
A process according to claim 12 wherein said diisocyanate is tolylene-2,4-diisocyanate or hexamethylene diisocyanate.
Claim 15
Dependent Claim
17 words
A process according to claim 9 wherein said cross-linking agent is epichlorohydrin in a sodium hydroxide solution.
Claim 16
Dependent Claim
17 words
A process according to claim 9 wherein said cross-linking agent is formaldehyde in a hydrochloric acid solution.
Claim 17
Dependent Claim
12 words
A process according to claim 9 wherein said cross-linking agent is glutaraldehyde.
Claim 18
Dependent Claim
11 words
Porous cellulose beads produced according to the process of claim 1.
Claim 19
Dependent Claim
12 words
Porous cross-linked cellulose beads produced according to the method of claim 9.
Claim 20
Dependent Claim
48 words
A method for the removal of metallic ions from a dilute solution containing said ions which comprises contacting the dilute solution with the porous cellulose beads of claim 17, said beads being further characterized by the presence of functional groups capable of attaching said ions to the beads.
Claim 21
Dependent Claim
48 words
A method for the separation and purification of enzymes, proteins, and nucleic acids which comprises contacting enzymes, proteins or nucleic acids with the porous beads of claim 17, said beads being further characterized by the presence of functional groups capable of attaching said enzymes, proteins or nucleic acids.
References Cited (Backward Citations)
US2118663A
Cited
US2543928A
Cited
US2773027A
Cited
US2843583A
Cited
US3251824A
Cited
US3501419A
Cited
US3236669A
Cited
US3505299A
Cited
US3746621A
Cited
US3573277A
Cited
US3739049A
Cited
US3905954A
Cited
US3936441A
Cited
US3947325A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |