Abstract: A process for the preparation of a composite biomaterial comprising: providing a first substantially solid component comprising one or more of collagen, a glycosaminoglycan, albumin, hyaluronan, chitosan, and synthetic polypeptides comprising a portion of the polypeptide sequence of collagen, and optionally an inorganic material, said component having at least a surface portion that is porous; providing a fluid composition comprising one or more of collagen, a glycosaminoglycan, albumin, hyaluronan, chitosan, and synthetic polypeptides comprising a portion of the polypeptide sequence of collagen, and a liquid carrier, and optionally an inorganic material; contacting said fluid composition with said porous surface portion of said first component; cooling said fluid composition to a temperature at which the liquid carrier transforms into a plurality of solid crystals or particles; removing at least some of the plurality of solid crystals or particles by sublimation and/or evaporation.

Abstract: A process for the preparation of a composite biomaterial comprising: providing a first substantially solid component comprising one or more of collagen, a glycosaminoglycan, albumin, hyaluronan, chitosan, and synthetic polypeptides comprising a portion of the polypeptide sequence of collagen, and optionally an inorganic material, said component having at least a surface portion that is porous; providing a fluid composition comprising one or more of collagen, a glycosaminoglycan, albumin, hyaluronan, chitosan, and synthetic polypeptides comprising a portion of the polypeptide sequence of collagen, and a liquid carrier, and optionally an inorganic material; contacting said fluid composition with said porous surface portion of said first component; cooling said fluid composition to a temperature at which the liquid carrier transforms into a plurality of solid crystals or particles; removing at least some of the plurality of solid crystals or particles by sublimation and/or evaporation.

Abstract: This invention relates to a method for fabricating large scaffolds in a variety of shapes with an organized pore structure. The pore structure is organized such that pores are generally aligned perpendicular to the edges of the scaffold, regardless of-the particular macroscopic scaffold shape. Specifically, a freeze-drying based fabrication method for creating large, polymeric porous scaffolds for tissue engineering applications, with an organized pore structure of columnar pores extending from the scaffold periphery into the main mass of the scaffold.

Abstract: This invention relates to highly porous scaffolding and methods of producing the same. Specifically, the scaffolding comprises a pore volume fraction of no less than 80% (v/v) of the total volume of the scaffold and interconnecting pores forming channels in the scaffold.

Abstract: The present invention relates to a process for fabricating molded structures having a radially organized pore structure. The molded structures are formed using a spinning-induced sedimentation technique such that sedimentation of a multi-component liquid suspension produces the internal geometry and porosity of the structure. The porous molded structures of the invention can be used in a number of applications including tissue and organ engineering, dialysis and phase separation membranes and water and liquid waste purification systems.

Abstract: The present invention relates to a method of skin regeneration of a wound or burn in an animal or human. This method comprises the steps of initially covering the wound with a collagen glycosaminoglycan matrix, allowing infiltration of the grafted GC matrix by mesenchymal cells and blood vessels from healthy underlying tissue and applying a cultured epithelial autograft sheet grown from epidermal cells taken from the animal or human at a wound free site on the animal's or human's body surface. The resulting graft has excellent take rates and has the appearance, growth, maturation and differentiation of normal skin.

Abstract: The present invention relates to a method of skin regeneration of a wound or burn in an animal or human. This method comprises the steps of initially covering the wound with a collagen glycosaminoglycan matrix, allowing infiltration of the grafted GC matrix by mesenchymal cells and blood vessels from healthy underlying tissue and applying a cultured epithelial autograft sheet grown from epidermal cells taken from the animal or human at a wound free site on the animal's or human's body surface. The resulting graft has excellent take rates and has the appearance, growth, maturation and differentiation of normal skin.

Abstract: A method for producing a biodegradable polymer having a preferentially oriented pore structure and a method for using the polymer to regenerate damaged nerve tissue is disclosed. The preferentially oriented pores are produced by an axial freezing process and serve to promote proper vascularation and regeneration of the damaged nerve. Preferably, the biodegradable polymer comprises uncrosslinked collagen-glycosaminoglycan.

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.

Abstract: Process for forming a multilayer blood vessel prosthesis. Each layer is formed from bioreplaceable materials which include those produced by contacting collagen with an aminopolysaccharide and subsequently covalently crosslinking the resluting polymer, polymers of hydroxyacetic acid and the like. Cross flow filtration molding and wet extrusion molding are two processes which are particularly useful for forming the inner layer of the blood vessel prosthesis. The outer layer of the blood vessel prosthesis is preferably formed by freeze drying a dispersion of the bioreplaceable material onto the inner layer(s). The disclosed blood vessel prosthesis is a multilayer structure with each layer having a porosity and other physicochemical and mechanical characteristics selected to maximize the effectiveness of the blood vessel. The prosthesis funcitons initially as a thromboresistant conduit with mechanical properties which match those of the adjacent natural blood vessel.

Abstract: Process for forming a multilayer blood vessel prosthesis. Each layer is formed from bioreplaceable materials which include those produced by contacting collagen with an aminopolysaccharide and subsequently covalently crosslinking the resulting polymer, polymers of hydroxyacetic acid and the like. Cross flow filtration molding and wet extrusion molding are two processes which are particularly useful for forming the inner layer of the blood vessel prosthesis. The outer layer of the blood vessel prosthesis is preferably formed by freeze drying a dispersion of the bioreplaceable material onto the inner layer(s). The disclosed blood vessel prosthesis is a multilayer structure with each layer having a porosity and other physicochemical and mechanical characteristics selected to maximize the effectiveness of the blood vessel. The prosthesis functions initially as a thromboresistant conduit with mechanical properties which match those of the adjacent natural blood vessel.

Abstract: A method for preserving the porosity of porous materials is disclosed. In this method, the porous material is subjected to elevated temperature and vacuum conditions to thereby produce a dimensionally-stable, non-collapsible porous material.

Abstract: This invention relates to the introduction of viable cells into a fibrous lattice by surgical, force-utilizing, or other manipulative techniques, all of which are referred to herein as "seeding." One embodiment comprises an autografting technique which involves intact tissue. Other embodiments which involve the distribution of an aqueous suspension of cells comprise centrifugal, spraying, pipetting and syringe emplacement. Each cell that survives the seeding process may reproduce into a colony of cells which grow until they reach confluence, thereby creating a uniform layer or volume of tissue. By proper placement of cells capable of generating such colonies, the period of recovery of a wound may be drastically reduced.

Abstract: This invention relates to the introduction of viable cells into a fibrous lattice by surgical, force-utilizing, or other manipulative techniques, all of which are referred to herein as "seeding." One embodiment comprises an autografting technique which involves intact tissue. Other embodiments which involve the distribution of an aqueous suspension of cells comprise centrifugal, spraying, pipetting and syringe emplacement. Each cell that survives the seeding process may reproduce into a colony of cells which grow until they reach confluence, thereby creating a uniform layer or volume of tissue. By proper placement of cells capable of generating such colonies, the period of recovery of a wound may be drastically reduced.

Abstract: A process for preparing a crosslinked collagen-glycosaminoglycan composite material which comprises forming an uncrosslinked composite material from collagen and a glycosaminoglycan and contacting the uncrosslinked composite with a gaseous aldehyde until a crosslinked product having an M.sub.c of from about 800 to about 60,000 is disclosed along with composite materials prepared by this process. Artificial skin produced by this process is more stable toward long-term storage than similar materials prepared using other methods of crosslinking.

Abstract: This invention comprises the use of centrifugal force to introduce viable cells into a fibrous lattice, as well as fibrous lattices that are seeded with cells by the use of centrifugal force. A variety of fibrous lattices may be seeded by the methods of this invention, such as a highly porous lattice comprising collagen fibers crosslinked with glycosaminoglycan. Before the centrifugation, a piece of intact tissue is harvested from a donor site. It is treated with one or more substances, such as trypsin or collagenase, to dissociate cells from the tissue. The cells are then mixed with an aqueous solution to create an aqueous suspension of cells. A piece of fibrous lattice is placed within a container, referred to herein as a "bucket," that is suitable for rotation by a centrifuge. The aqueous suspension of cells is placed within the bucket, in contact with the lattice. The centrifuge is then rotated.

Abstract: This invention relates to crosslinked collagen and glycosaminoglycan materials, and to procedures for preparing such materials. It has been discovered that if collagen fibrils in an aqueous acidic solution are contacted with a crosslinking agent before being contacted with glycosaminoglycan, the materials produced have extremely low levels of thrombogenicity. Such materials are well suited for in-dwelling catheters, blood vessel grafts, and other devices that are in continuous contact with blood for long periods of time.

Abstract: Composite materials are disclosed which are formed by contacting collagen with a mucopolysaccharide and subsequently covalently crosslinking the resultant polymer. These composite materials have a balance of mechanical, chemical and physiological properties which make them useful in surgical sutures and prostheses of controlled biodegradability (resorption) and controlled ability to prevent development of a foreign body reaction, and many are also useful in applications in which blood compatibility is required.

Abstract: A cross flow filtration molding apparatus and method are disclosed which are particularly useful for forming complicated shapes from dispersions of particles in a liquid medium. Dispersion is pumped through a mold which has porous walls and a sufficient pressure differential is applied to drive a portion of the liquid medium through the porous walls which results in deposition of particles on the walls to form a shaped article. The shaped article may inherently have sufficient structural integrity, or it may be post-treated to provide additional structural integrity.

Abstract: A multilayer membrane, which is useful as synthetic skin, is disclosed herein. A first layer is formed from a material which does not provoke an immune response and which is also insoluble and nondegradable in the presence of body fluids and/or body enzymes. Preferred materials for the first layer are crosslinked composites of collagen and a mucopolysaccharide. A second layer is formed from a nontoxic material which controls the moisture flux of the overall membrane to about 0.1 to 1 mg./cm.sup.2 /hr. Suitable materials for the second layer include synthetic polymers such as silicone resins, polyacrylate or polymethacrylate esters or their copolymers, and polyurethanes.