Abstract: A permeable structure forms a chamber to hold living cells. The structure includes a first permeable region surrounding at least a portion of the chamber having a conformation that, when implanted in host tissue, substantially blocks penetration of host cells into the chamber while permitting solute transport. The structure also includes a second permeable region overlying the first permeable region having a conformation that, when implanted in host tissue, forms a permeable interface with host tissue that permits solute transport. A third permeable region is located between the first and second permeable regions. The third region comprises a solution of polymer material formed in place between the first and second permeable regions. The third permeable region bonds the first and second permeable regions together. The third permeable region also has a conformation that, when implanted in host tissue, permits solute transport between the first and second permeable regions.

Abstract: A device for implantation in a host having a material at an interface between the host and the device, said material having a conformation which results in growth of vascular structures by the host close to the interface.

Abstract: A device for implantation in a host having a material at an interface between the host and the device, said material having a conformation which results in growth of vascular structures by the host close to the interface.

Abstract: Polymer membrane structures are microfabricated from polyimide film by lithography or etching. The microfabricated structures have systematically varied dimensions and geometries conducive to implanting in host tissue and the promotion, when implanted, of new vascular structures.

Abstract: A device for implantation in a host having a material at an interface between the host and the device, said material having a conformation which results in growth of vascular structures by the host close to the interface.

Abstract: A device for implantation in a host having a material at an interface between the host and the device, said material having a conformation which results in growth of vascular structures by the host close to the interface.

Abstract: A device for implantation in a host having a material at an interface between the host and the device, said material having a conformation which results in growth of vascular structures by the host close to the interface.

Abstract: A method for implanting cells is disclosed which employs a chamber having a wall forming porous boundary between the host and implanted cells. According to the method, a given number of cells (N) is placed within the porous boundary of a given area (A) such that the quantity A/N is less than about 200 .mu.m.sup.2 /cell. The porous boundary has a pore size, an ultimate strength, and a metabolic transit value that assures the survival of the cells during the critical ischemic period and afterward.

Abstract: Methods for enhancing vascular support of cells housed within an implanted apparatus are disclosed. The methods comprise placing a population of therapeutic substance-producing cells into the cell receiving chamber of an immunoisolation apparatus, implanting the apparatus into a patient, and administering an immunomodulatory agent to the patient. The immunomodulatory agent increases the number of close vascular structures in the vicinity of the implanted device, which increases the long term survival of the cell population housed therein.

Abstract: Implant assemblies and methodologies provide immuno-protection for implanted allografts, xenografts, and isografts. The assemblies and methodologies establish a boundary between the host and the implanted cells. The boundary has a pore size, an ultimate strength, and a metabolic transit value that assures the survival of the cells during the critical ischemic period and afterward. The boundary allows the fabrication and clinical use of implant assemblies and methodologies that can carry enough cells to be of therapeutic value to the host, yet occupy a relatively small, compact area within the host.