Inner supported biocompatible cell capsules

Abstract

A biocompatible capsule for containing cells for implantation is prepared containing an inner support that provides tensile strength to the capsule. Cells within the capsule are suspended in a liquid medium or immobilized in a hydrogel or extracellular matrix material, and are surrounded by a semipermeable membrane across which biologically active molecules can be delivered from the capsule to surroundings or from the surroundings into the capsule. The inner support may be formed as an integral part of the capsule during a coextrusion process to form the capsule. Alternatively, the inner support may be a discrete component within a tube having top and bottom sealing fittings that are linked withing the tube by the support. The inner support may have external features such as flutes or a roughened or irregularly-shaped surface, and may be coated with cell-adhesive substance or a cell-viability-enhancing substance. The inner support may be a hollow tube having two channels, one communicating with a filling port that permits injecting cells through the support into the capsule and the other communicating with another port that allows gas to escape through the support as cells are introduced. The capsule may be made immunoisolatory by controlling membrane permselectivity or by substances in the membrane that reduce immune response, and may contain a tether for retrieval that can be formed integrally with the inner support.