US5686091A
Expired / Lapsed
US
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Biodegradable foams for cell transplantation
Assignee: Johns Hopkins University
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Filing: 1994-03-28
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Granted: 1997-11-11
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Expires: 2014-03-28
Abstract
Abstract A structurally rigid biodegradable foam scaffold useful for cell transplantation is provided. The foam can be loaded with nutrients and/or drugs that elute from the foam during transplant to promote growth of the cells. The foam, which features a continuous network of pores, is fabricated using a novel method involving phase separation and consequent expansion upon sublimation of a liquid solvent, preferably naphthalene.
Inventors
- 👤 Kam W. Leong
- 👤 Hungnan Lo
- 👤 Sudhakar Kadiyala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:29
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/022; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249958; Y10T428/249978
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
122 words
A method for producing a biocompatible and biodegradable porous foam comprising: a) dissolving from about 0.5 to 10 weight percent of a biocompatible polymer in a liquid solvent having a melting point in the range from about 30° to about 90° C. to form a polymer solution; b) placing the solvent solution onto a form under conditions promoting spinodal decomposition in the solution; c) quenching the polymer solution in the form; d) sublimating the solvent in the solution; and e) obtaining a biocompatible porous foam comprising a substantially continuous polymer phase and a substantially continuous gas phase with substantially uniform pore size and pore distribution and having an average pore size in the range from about 20 to 500 μm, in diameter.
Claim 2
Independent Claim
122 words
A method for producing a biocompatible and biodegradable porous foam comprising: a) dissolving from about 0.5 to 10 weight percent of a biocompatible polymer in a liquid solvent having a melting point in the range from about 30° to about 90° C. to form a polymer solution; b) placing the solvent solution onto a form under conditions promoting spinodal decomposition in the solution; c) quenching the polymer solution in the form; d) sublimating the solvent in the solution; and e) obtaining a biocompatible porous foam comprising a substantially continuous polymer phase and a substantially continuous gas phase with substantially uniform pore size and pore distribution and having an average pore size in the range from about 20 to 500 μm, in diameter.
Claim 3
Dependent Claim
10 words
The method of claim 1 wherein the solvent is naphthalene.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the placing is by spraying the polymer solution onto the form in layers.
Claim 5
Dependent Claim
11 words
The method of claim 1 wherein the form is a mold.
Claim 6
Dependent Claim
15 words
The method of claim 4 wherein the mold is in the shape of a bone.
Claim 7
Dependent Claim
27 words
The method of claim 1 wherein from about 1 to 10 weight percent of a cell growth nutrient is added to the polymer solution in step a).
Claim 8
Dependent Claim
41 words
The method of claim 6 wherein the nutrient is selected from the group consisting of enzymes, bone morphogenetic proteins (BMP), epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), insulin-like growth factor (IGF-I and -II), TGF-β, and dexamethason.
Claim 9
Dependent Claim
11 words
The method of claim 1 wherein the polymer comprises polylactic acid.
Claim 10
Dependent Claim
41 words
The method of claim 8 wherein the pore surface area is from about 1.2905 to 0.79 m 2 /g, the pore volume is from about 17.747 to 7.198 cm 3 /g, and the porosity is from about 87 to 71 percent.
Claim 11
Dependent Claim
19 words
The method of claim 9 wherein the polymer solution is quenched while in the early stages of spinodal decomposition.
Claim 12
Dependent Claim
11 words
The method of claim 1 wherein the polymer is a polyphosphoester.
Claim 13
Dependent Claim
21 words
The method of claim 1 further comprising adding a therapeutic amount of a drug to the polymer solution in step a).
Claim 14
Dependent Claim
19 words
The method of claim 12 wherein the polymer solution is quenched while in the early stages of spinodal decomposition.
Claim 15
Dependent Claim
51 words
A three dimensional biocompatible and biodegradable porous foam comprising a substantially continuous polymer phase and a substantially continuous gas phase with substantially uniform pore size and pore distribution and having an average pore size in the range from about 20 to 500 μm; and cultured tissue cells contained within the pores.
Claim 16
Dependent Claim
51 words
A three dimensional biocompatible and biodegradable porous foam comprising a substantially continuous polymer phase and a substantially continuous gas phase with substantially uniform pore size and pore distribution and having an average pore size in the range from about 20 to 500 μm; and cultured tissue cells contained within the pores.
Claim 17
Dependent Claim
13 words
The porous foam of claim 14 wherein the polymer phase comprises polylactic acid.
Claim 18
Dependent Claim
42 words
The porous foam of claim 15 wherein the pore surface area is from about 1.2905 to 0.79 m 2 /g, the pore volume is from about 17.747 to 7.198 cm 3 /g, and the porosity is from about 87 to 71 percent.
Claim 19
Dependent Claim
15 words
The porous foam of claim 15 wherein the polymer phase further comprises a cell nutrient.
Claim 20
Dependent Claim
18 words
The porous foam of claim 15 wherein the polymer phase further comprises a therapeutic amount of a drug.
Claim 21
Dependent Claim
21 words
The porous foam of claim 14 wherein the density of the cultured tissue cells is about 10 4 cells/ml of culture.
Claim 22
Dependent Claim
34 words
A biodegradable and biocompatible porous foam comprising a substantially continuous polymer phase and a substantially continuous gas phase with substantially uniform pore size and pore distribution, said foam also including a cell growth nutrient.
Claim 23
Dependent Claim
34 words
A biodegradable and biocompatible porous foam comprising a substantially continuous polymer phase and a substantially continuous gas phase with substantially uniform pore size and pore distribution, said foam also including a cell growth nutrient.
Claim 24
Dependent Claim
14 words
The porous foam according to claim 20 including cultured tissue cells in the pores.
Claim 25
Dependent Claim
12 words
The porous foam according to claim 20 including at least one drug.
Claim 26
Dependent Claim
20 words
The method of claim 1 including adding a cell growth nutrient to the polymer solution while forming the polymer solution.
Claim 27
Dependent Claim
11 words
The method of claim 1 wherein the polymer comprises a co-polymer.
References Cited (Backward Citations)
US3812224A
Cited
US4186448A
Cited
US4826945A
Cited
US5256765A
Cited
US5035713A
Cited
US5102983A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-11-10 | 2001-05-12 | 2001-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-10 | 2005-05-12 | 2005-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-10 | 2009-05-12 | 2009-11-11 | $7700.00 | Window Closed / Lapsed |