# US 11,110,207 B2 · Nerve repair scaffolds having high microchannel volume and methods for making the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,110,207 B2 - Document ID: US11110207B2 - Status: Granted - Kind: B2 - Application number: 16/545,855 - Filed: 2019-08-20 - Published: 2020-01-02 - Granted: 2021-09-07 - Earliest claimed: 2015-10-07 - Assignees: The Regents of the University of Michigan; The Regents of the University of California; The United States Government as represented by the Department of Veterans Affairs - Applicants: The Regents of the University of Michigan; The Regents of the University of California; The United States of America AS Represented By the Department of Veterans Affairs - Inventors: Jeffrey S. Sakamoto; Dena Shahriari; Mark H. Tuszynski; Wendy Campana; Yacov Koffler - Web page: https://patentgrep.com/patent/US11110207B2 ## CPC - A61L 27/56: Porous materials, {e.g. foams or sponges} - A61L 27/18: obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds - A61L 27/34: Macromolecular materials - A61L 27/58: Materials at least partially resorbable by the body - A61L 27/54: Biologically active materials, e.g. therapeutic substances {(A61L27/227 takes precedence)} - A61L 2300/252: Polypeptides, proteins, e.g. glycoproteins, lipoproteins, cytokines - A61L 2300/412: Tissue-regenerating or healing or proliferative agents - A61L 2430/32: for nerve reconstruction - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) ## Abstract Tissue scaffolds for neural tissue growth have a plurality of microchannels disposed within a sheath. Each microchannel comprises a porous wall having a thickness of ≤about 100 μm that is formed from a biocompatible and biodegradable material comprising a polyester polymer. The polyester polymer may be polycaprolactone, poly(lactic-co-glycolic acid) polymer, and combinations thereof. The tissue scaffolds have high open volume % enabling superior (linear and high fidelity) neural tissue growth, while minimizing inflammation near the site of implantation in vivo. In other aspects, methods of making such tissue scaffolds are provided. Such a method may include mixing a reduced particle size porogen with a polymeric precursor solution. The material is cast onto a template and then can be processed, including assembly in a sheath and removal of the porogen, to form a tissue scaffold having a plurality of porous microchannels. ## Claims ### Claim 1 A tissue scaffold for neural tissue growth comprising: a sheath; and a plurality of microchannels disposed within the sheath, wherein each microchannel of the plurality comprises (i) a biocompatible and biodegradable material comprising a polyester polymer, and (ii) a porous wall comprising a plurality of pores haying an average pore size of greater than or equal to about 10 m to less than or equal to about 50 m, wherein the porous wall has a thickness of greater than or equal to about 10 m to less than or equal to about 100 m and is free line-of-sight porosity to prevent or minimize cellular growth through the porous wall. ### Claim 2 (depends on 1) The tissue scaffold of claim 1, wherein the tissue scaffold has an open volume of greater than or equal to about 50 volume %. ### Claim 3 (depends on 1) The tissue scaffold of claim 1, wherein the tissue scaffold has an average open volume of greater than or equal to about 90 volume %. ### Claim 4 (depends on 1) The tissue scaffold of claim 1, wherein the porous wall has a thickness of greater than or equal to about 10 μm to less than or equal to about 70 μm and a diameter of each microchannel is less than or equal to about 500 μm. ### Claim 5 (depends on 1) The tissue scaffold of claim 1, wherein the plurality of microchannels are closely packed within the sheath, so that a portion of each microchannel contacts another microchannel of the plurality. ### Claim 6 (depends on 1) The tissue scaffold of claim 1, wherein each microchannel of the plurality of microchannels has an oval or spherical cross-section and the plurality of microchannels are arranged within the sheath in a close-packed array. ### Claim 7 (depends on 1) The tissue scaffold of claim 1, wherein the polyester polymer is selected from a group consisting of: polycaprolactone, poly(lactic-co-glycolic acid) polymer, and combinations thereof. ### Claim 8 (depends on 1) The tissue scaffold of claim 1, wherein the average pore size is greater than or equal to about 10 μm to less than or equal to about 20 μm. ### Claim 9 (depends on 1) The tissue scaffold of claim 1, wherein a surface of the porous wall has a coating comprising a material for promoting growth of neural tissue selected from the group consisting of: fibronectin, keratin, laminin, collagen, and combinations thereof. ### Claim 10 (depends on 1) The tissue scaffold of claim 1, wherein the tissue scaffold facilitates neural tissue growth through the plurality of microchannels from a first end to a second opposite end, but avoids neural tissue growth from an interior region to an exterior region of each microchannel of the plurality. ### Claim 11 (depends on 1) The tissue scaffold of claim 1, wherein a microchannel density of the plurality of microchannels in the tissue scaffold is greater than or equal to about 1 to less than or equal to about 300 microchannels/mm2 in the tissue scaffold. ### Claim 12 (depends on 11) The tissue scaffold of claim 11, wherein the microchannel density is greater than or equal to about 30 to less than or equal to about 120 microchannels/mm2 in the tissue scaffold. ### Claim 13 A tissue scaffold for neural tissue growth comprising: a porous sheath having a first length and comprising a first plurality of pores having an average pore size of greater than or equal to about 10 μm to less than or equal to about 50 μm; and a plurality of microchannels disposed within the sheath defining a second length, wherein each microchannel of the plurality comprises (i) a biocompatible and biodegradable material comprising a polyester polymer, and (ii) a porous wall comprising a second plurality of pores having an average pore size of greater than or equal to about 10 μm to less than or equal to about 50 μm, wherein the porous wall has a thickness of greater than or equal to about 10 μm to less than or equal to about 100 μm and is free of line-of-sight porosity to prevent or minimize cellular growth through the porous wall, wherein the first length is greater than the second length and the tissue scaffold has an open volume of greater than or equal to about 60 volume %. ### Claim 14 (depends on 13) The tissue scaffold of claim 13, wherein the porous sheath defines a first end and a second end, wherein the porous sheath extends at least about 1.5 mm past the first end and the second end and is configured to receive at least one suture. ### Claim 15 (depends on 13) The tissue scaffold of claim 13, wherein the biocompatible and biodegradable material is a first biocompatible and biodegradable material and the porous sheath is formed of a second biocompatible and biodegradable material distinct from the first biocompatible and biodegradable material. ### Claim 16 (depends on 13) The tissue scaffold of claim 13, wherein the biocompatible and biodegradable material is a first biocompatible and biodegradable material and the porous sheath is formed of a second biocompatible and biodegradable material, wherein the first biocompatible and biodegradable material and the second biocompatible and biodegradable material are independently selected from the group consisting of: polycaprolactone, poly(lactic-co-glycolic acid) polymer, and combinations thereof. ### Claim 17 (depends on 13) The tissue scaffold of claim 13, wherein the average pore size of the second plurality of pores is greater than or equal to about 10 μm to less than or equal to about 20 μm. ### Claim 18 A tissue scaffold for neural tissue growth comprising: a porous sheath; and a plurality of microchannels disposed within and closely packed in the porous sheath, so that a portion of each microchannel contacts another microchannel of the plurality and each microchannel of the plurality comprises (i) a biocompatible and biodegradable material comprising a polyester polymer, and (ii) a porous wall comprising a plurality of pores having an average pore size of greater than or equal to about 10 μm to less than or equal to about 50 μm, wherein the porous wall has a thickness of greater than or equal to about 10 μm to less than or equal to about 100 μm and is free of line-of-sight porosity to prevent or minimize cellular growth through the porous wall, wherein the tissue scaffold has an open volume of greater than or equal to about 60 volume %. ### Claim 19 (depends on 18) The tissue scaffold of claim 18, wherein each microchannel of the plurality of microchannels has an oval or spherical cross-section and the plurality of microchannels are arranged within the porous sheath in a close-packed array. ### Claim 20 (depends on 18) The tissue scaffold of claim 18, wherein the porous sheath has a cross-sectional shape selected from an oval, a sphere, and a butterfly.