Donor islets are marked as ‘foreign’ by the host immune system which eventually leads to their rejection. Therefore, transplantation of donor islet cells into a recipient requires life-long treatment with deleterious immunosuppressive drugs.
The βAir device has efficiently solved this problem by replacing drugs for an isolated microenvironment, a kind of an immune privileged site, which is separated from the host immune system by an effective immune barrier, a permselective membrane.
The immune barrier covering the active surfaces of the device is composed of two adjoining, thin and porous plastic membranes. By itself, this barrier prevents cell-cell contact, thereby disabling part of the cellular host immune response. However, it is still permeable to most of the humoral immune system components. By impregnating the adjoined membranes with a specific hydrogel, a potent permselective membrane is being created. It is impermeable to macromolecules (e.g. antibodies and complement family members) while still allowing free passage of glucose, small nutrient molecules, glucagon and insulin.
The proprietary permselective membrane is one of the keys features contributing to the success of ßAir BAP device. The contained islets are able to sense the level of tissue glucose thereby regulating the production of the pancreatic hormones as they do in their native site.