Multiple-layer, formed-in-place immunoisolation membrane structures for

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. The third, formed-in-place region bonds the first and second permeable regions together, providing a robust, laminated structure that resists delamination during implantation caused by cellular infiltration into discontinuous spaces between the first and second regions. The third, formed-in-place region can also have a conformation providing an immunoisolation effect. Furthermore, the permeability of the third, formed-in-place membrane is sufficient high that it does not adversely effect the permeability value desired for the overall multiple layer membrane structure.