US4947840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biodegradable templates for the regeneration of tissues
Assignee: Massachusetts Institute of Technology
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Filing: 1987-08-21
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Granted: 1990-08-14
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Expires: 2007-08-21
Abstract
Abstract This invention relates to porous, biodegradable materials in which the pore size, biodegradation rate, and pore volume fraction are controlled and within values at which skin contraction rates around an implant-containing wound are delayed or slowed.
Inventors
- 👤 Ioannis V. Yannas
- 👤 Elaine Lee
- 👤 Ariel Ferdman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:44
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/14; A61L27/22; A61L27/24; A61L27/20; A61L27/50; A61L27/56; A61L27/58; C; C08; C08B; C08B37/00; C08B37/006; C08B37/0063; A61F; A61F2310/00; A61F2310/00005; A61F2310/00365; Y; Y10; Y10S; Y10S424/00; Y10S424/13
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
80 words
A method of delaying or arresting contraction of skin bordering a wound site and promoting tissue regeneration, comprising applying a biodegradable material with a pore size of between about 9 μm and 630 μm, a pore volume fraction of greater than about 80%, and a biodegradation rate sufficient to significantly delay or arrest the rate of wound contraction such that the time it takes a wound to contract to one-half of its original area is greater than approximately 15 days.
Claim 2
Independent Claim
80 words
A method of delaying or arresting contraction of skin bordering a wound site and promoting tissue regeneration, comprising applying a biodegradable material with a pore size of between about 9 μm and 630 μm, a pore volume fraction of greater than about 80%, and a biodegradation rate sufficient to significantly delay or arrest the rate of wound contraction such that the time it takes a wound to contract to one-half of its original area is greater than approximately 15 days.
Claim 3
Dependent Claim
13 words
A method as in claim 1 wherein the biodegradable material comprises collagen molecules.
Claim 4
Dependent Claim
36 words
A method as in claim 1 wherein the biodegradable material comprises collagen molecules that are crosslinked and covalently bonded with a second material selected from the group consisting of glycosaminoglycans, glycoproteins, structural proteins and growth factors.
Claim 5
Dependent Claim
33 words
A method as in claim 3 wherein the second material is a glycosaminoglycan selected from the group consisting of chondroitin 6-sulfate, chondroitin 4-sulfate, heparin, heparan sulfate, keratan sulfate, dermatan sulfate, chitin and chitosan.
Claim 6
Dependent Claim
23 words
A method as in claim 3 wherein the second material is a glycoprotein selected from the group consisting of fibronectin, laminin and chondronectin.
Claim 7
Dependent Claim
16 words
A method as in claim 3 wherein the second material is a structural protein comprising elastin.
Claim 8
Dependent Claim
35 words
A method as in claim 3 wherein the second material is a growth factor selected from the group consisting of epidermal growth factor, platelet derived growth factor, tissue angiogenesis growth factor and bone growth factor.
Claim 9
Dependent Claim
19 words
A method as in claim 3 wherein the biodegradable material is crosslinked by contacting it with an aqueous aldehyde.
Claim 10
Dependent Claim
11 words
A method as in claim 8 wherein the aldehyde is glutaraldehyde.
Claim 11
Dependent Claim
25 words
A method as in claim 1 wherein the biodegradable material contains pores with an average size ranging from about 20 μm to about 125 μm.
Claim 12
Dependent Claim
26 words
A method as in claim 1 wherein the biodegradable material has a degradation rate in an in vitro collagenase assay of below about 140 enzyme units.
Claim 13
Dependent Claim
25 words
A method as in claim 11 wherein the biodegradable material has a degradation rate in an in vitro collagenase-assay of below about 120 enzyme units.
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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) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |