Patent US726029A successfully refreshed from Google Patents.
US5871985A
Expired / Lapsed
US
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Particulate non cross-linked chitosan core matrices for encapsulated cells
Assignee: Brown University Research Foundation Inc
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Filing: 1994-08-22
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Granted: 1999-02-16
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Expires: 2014-08-22
Abstract
Abstract Vehicles containing cells for implanting in the tissue of an individual are prepared having cells dispersed in a particulate, essentially non cross-linked chitosan core matrix that is enclosed within a semipermeable membrane. The cells are entrapped between chitosan particles of the core matrix and there is essentially no interfacial cross-linking between the core matrix and the membrane. The core matrix provides a physical support for viable cells within the vehicle such that the cells are evenly dispersed throughout the core matrix so as to allow their maintenance, growth, proliferation and differentiation. The vehicle can be prepared by mixing viable cells with a solution of chitosan, encapsulating the resultant mixture in a semipermeable membrane and causing the chitosan to precipitate such as by changing the pH to form the core matrix. Alternatively, the chitosan is precipitated to form the core matrix containing cells and then the core matrix is encapsulated in a semipermeable membrane. Cells within the core matrix may be neurosecretory cell lines, beta -cell-derived cells lines, fibroblasts, myocytes and glial cells.
Inventors
- 👤 Patrick Aebischer
- 👤 Beth A. Zielinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:27
CPC Classifications
C; C12; C12N; C12N5/00; C12N5/0012; A; A61; A61L; A61L27/00; A61L27/14; A61L27/20; A61L27/36; A61L27/38; A61L27/3804; A61L27/3895; C12N5/06; C12N5/0602; C12N5/0618; C12N5/0619; A61K; A61K35/00; A61K35/12; A61K2035/126; A61K2035/128
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
113 words
A method for making a tissue implantable vehicle comprising viable cells within a core matrix, said method comprising the steps of: (a) mixing a solution of dissolved chitosan with viable cells, (b) encapsulating the mixture of (a) within a semipermeable membrane to form a vehicle, and (c) causing said chitosan to precipitate to form an essentially non cross-linked, particulate chitosan core matrix, while avoiding formation of a cross-linked chitosan solid or gel, wherein there is essentially no interfacial cross-linking between said matrix and said membrane, wherein said viable cells are dispersed within said core matrix and wherein said particulate core matrix does not restrict the ability of the cells to divide and expand.
Claim 2
Independent Claim
113 words
A method for making a tissue implantable vehicle comprising viable cells within a core matrix, said method comprising the steps of: (a) mixing a solution of dissolved chitosan with viable cells, (b) encapsulating the mixture of (a) within a semipermeable membrane to form a vehicle, and (c) causing said chitosan to precipitate to form an essentially non cross-linked, particulate chitosan core matrix, while avoiding formation of a cross-linked chitosan solid or gel, wherein there is essentially no interfacial cross-linking between said matrix and said membrane, wherein said viable cells are dispersed within said core matrix and wherein said particulate core matrix does not restrict the ability of the cells to divide and expand.
Claim 3
Dependent Claim
27 words
A method according to claim 1 wherein said cells are selected from the group consisting of neurosecretory cell lines, β-cell-derived cell lines, fibroblasts, myocytes, and glial cells.
Claim 4
Dependent Claim
29 words
A method according to claim 2 wherein the neurosecretory cell lines are PC12 cells, the β-cell-derived cell lines are NIT or RIN cells, and the glial cells are astrocytes.
Claim 5
Dependent Claim
17 words
An implantable vehicle comprising cells within a core matrix made according to the method of claim 1.
Claim 6
Dependent Claim
28 words
The method of claim 1 wherein the chitosan precipitation of step (c) occurs by placing said vehicle formed in step (b) in a buffered solution comprising monovalent anions.
Claim 7
Independent Claim
142 words
A method for making a tissue implantable vehicle comprising viable cells within a core matrix, said method comprising the steps of: (a) preparing an aqueous chitosan solution; (b) mixing the solution of (a) with viable cells to form a mixture having a first pH; (c) encapsulating the mixture of (b) with a semipermeable membrane to form a vehicle, and (d) adjusting the first pH to a second pH which is higher than said first pH to cause said chitosan to precipitate to form an essentially non cross-linked, particulate chitosan core matrix, while avoiding formation of a cross-linked chitosan solid or gel, wherein there is essentially no interfacial cross-linking between said matrix and said membrane, wherein said viable cells are dispersed within said core matrix and wherein said particulate core matrix does not restrict the ability of the cells to divide and expand.
Claim 8
Independent Claim
142 words
A method for making a tissue implantable vehicle comprising viable cells within a core matrix, said method comprising the steps of: (a) preparing an aqueous chitosan solution; (b) mixing the solution of (a) with viable cells to form a mixture having a first pH; (c) encapsulating the mixture of (b) with a semipermeable membrane to form a vehicle, and (d) adjusting the first pH to a second pH which is higher than said first pH to cause said chitosan to precipitate to form an essentially non cross-linked, particulate chitosan core matrix, while avoiding formation of a cross-linked chitosan solid or gel, wherein there is essentially no interfacial cross-linking between said matrix and said membrane, wherein said viable cells are dispersed within said core matrix and wherein said particulate core matrix does not restrict the ability of the cells to divide and expand.
Claim 9
Dependent Claim
27 words
A method according to claim 6 wherein said cells are selected from the group consisting of neurosecretory cell lines, β-cell-derived cell lines, fibroblasts, myocytes, and glial cells.
Claim 10
Dependent Claim
29 words
A method according to claim 7 wherein the neurosecretory cell lines are PC12 cells, the B-cell-derived cell lines are NIT or RIN cells, and the glial cells are astrocytes.
Claim 11
Dependent Claim
17 words
An implantable vehicle comprising cells within a core matrix made according to the method of claim 6.
Claim 12
Dependent Claim
15 words
The implantable vehicle of claim 4 or 9 wherein said viable cells are PC12 cells.
Claim 13
Dependent Claim
15 words
The implantable vehicle of claim 4 or 9 wherein said viable cells are NIT cells.
Claim 14
Dependent Claim
15 words
The implantable vehicle of claim 4 or 9 wherein said viable cells are RIN cells.
Claim 15
Dependent Claim
14 words
The implantable vehicle of claim 4 or 9 wherein said viable cells are astrocytes.
Claim 16
Independent Claim
143 words
A method for inoculating a tissue culture comprising: (a) dissolving a predetermined amount of chitosan in an aqueous solution; (b) mixing the solution of (a) with viable cells in the absence of cross-link inducing substances; (c) enclosing the mixture of (b) with a semipermeable membrane; (d) causing the chitosan in (c) to precipitate to form an essentially non cross-linked, particulate chitosan core matrix, while avoiding formation of a cross-linked chitosan solid or gel, wherein there is essentially no interfacial cross-linking between said matrix and said membrane, wherein said viable cells are dispersed within said core matrix and wherein said particulate core matrix does not restrict the ability of the cells to divide and expand; (e) growing the cells within the particulate chitosan to form a viable cell containing matrix, and (f) inoculating a tissue culture with the enclosed cell containing matrix of (e).
Claim 17
Independent Claim
143 words
A method for inoculating a tissue culture comprising: (a) dissolving a predetermined amount of chitosan in an aqueous solution; (b) mixing the solution of (a) with viable cells in the absence of cross-link inducing substances; (c) enclosing the mixture of (b) with a semipermeable membrane; (d) causing the chitosan in (c) to precipitate to form an essentially non cross-linked, particulate chitosan core matrix, while avoiding formation of a cross-linked chitosan solid or gel, wherein there is essentially no interfacial cross-linking between said matrix and said membrane, wherein said viable cells are dispersed within said core matrix and wherein said particulate core matrix does not restrict the ability of the cells to divide and expand; (e) growing the cells within the particulate chitosan to form a viable cell containing matrix, and (f) inoculating a tissue culture with the enclosed cell containing matrix of (e).
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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) | 2002-02-15 | 2002-08-17 | 2003-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-02-15 | 2006-08-17 | 2007-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-02-15 | 2010-08-17 | 2011-02-16 | $7700.00 | Window Closed / Lapsed |