Patent US1060748A successfully refreshed from Google Patents.
US4063017A
Expired / Lapsed
US
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Porous cellulose beads and the immobilization of enzymes therewith
Assignee: Purdue Research Foundation
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Filing: 1976-04-22
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Granted: 1977-12-13
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Expires: 1996-04-22
Abstract
Abstract Porous cellulose beads are prepared by distributing droplets of a solvent mixture containing a cellulose derivative into an aqueous 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.
Inventors
- 👤 George T. Tsao
- 👤 Li Fu Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:46
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: 23
Claim 1
Independent Claim
170 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 selected from the group of a mixture of acetone and dimethylsulfoxide and a mixture of acetone and formamide 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
170 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 selected from the group of a mixture of acetone and dimethylsulfoxide and a mixture of acetone and formamide 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
18 words
A process according to claim 1 wherein said precipitation solution is an aqueous solution or liquid aliphatic hydrocarbon.
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
19 words
A process according to claim 1 wherein the void space of said beads is from about 75 to 95%.
Claim 8
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 9
Dependent Claim
15 words
A process according to claim 7 wherein said beads are cross-linked prior to being hydrolyzed.
Claim 10
Dependent Claim
14 words
A process according to claim 7 wherein said beads are cross-linked after being hydrolyzed.
Claim 11
Dependent Claim
13 words
A process according to claim 7 wherein said cross-linking agent is a diisocyanate.
Claim 12
Dependent Claim
14 words
A process according to claim 10 wherein said diisocyanate is tolylene-2,4-diisocyanate or hexamethylene diisocyanate.
Claim 13
Dependent Claim
17 words
A process according to claim 7 wherein said cross-linking agent is epichlorohydrin in a sodium hydroxide solution.
Claim 14
Dependent Claim
17 words
A process according to claim 7 wherein said cross-linking agent is formaldehyde in a hydrochloric acid solution.
Claim 15
Dependent Claim
12 words
A process according to claim 7 wherein said cross-linking agent is glutaraldehyde.
Claim 16
Dependent Claim
13 words
A process according to claim 1 wherein said cellulose derivative is cellulose acetate.
Claim 17
Dependent Claim
19 words
A process according to claim 15 wherein said inert organic, water-miscible solvent is a mixture of acetone and dimethylsulfoxide.
Claim 18
Dependent Claim
19 words
A process according to claim 16 wherein the ratio by volume of acetone to dimethylsulfoxide is 6 to 4.
Claim 19
Dependent Claim
19 words
A process according to claim 15 wherein said inert organic water-miscible solvent is a mixture of acetone and formamide.
Claim 20
Dependent Claim
18 words
A process according to claim 18 wherein the volume ratio of acetone to formamide is 7 to 3.
Claim 21
Dependent Claim
18 words
A process according to claim 1 wherein said porous cellulose beads are at least 0.11 mm in diameter.
Claim 22
Dependent Claim
12 words
Porous spherical cellulose beads produced according to the process of claim 1.
Claim 23
Dependent Claim
13 words
Porous cross-linked spherical cellulose beads produced according to the method of claim 7.
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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) | 1980-12-12 | 1981-06-13 | 1981-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-12 | 1985-06-13 | 1985-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-12 | 1989-06-13 | 1989-12-13 | $7700.00 | Window Closed / Lapsed |