Patent ID: 7943353

Claim:
A multi-layer microcapsule comprising bioactive cells attached to a microcapsule membrane; wherein said microcapsule membrane comprises (i) a first inner layer of biopolymer selected from the group consisting of cationic collagen, anionic collagen, anionic esterified hyaluronic acid, anionic amine-modified hyaluronic acid, fibronectin, and laminin; (ii) a second intermediate layer of polyelectrolyte synthetic polymer; and (iii) a third outer layer forming an exoskeleton to provide mechanical stability; wherein said first inner layer and said second intermediate layer are complexed via ionic charges; wherein said second intermediate layer and said third outer layer are complexed via ionic charges; wherein said microcapsule membrane is permeable to molecules smaller than or equal to the size of albumin, to nutrients necessary to sustain normal metabolic functions of the bioactive cells, and to toxins released by the bioactive cells; and wherein said microcapsule membrane is impermeable to immunoglobulins and macrophages.