Controlled release of dopamine, insulin and other agents from microencapsulated cells

Abstract

Mammalian cells encapsulated within polymeric membranes is a novel way for in vivo controlled release of therapeutic agents. A permselective polymeric membrane, by acting as a permeability barrier for large molecules (such as antibodies) can protect the encapsulated cells from the cytotoxic components of the host's tissue reaction without immunosuppressants. The high membrane permeability for small molecules (such as nutrients, hormones, etc.), on the other hand, will ensure the maintenance of normal physiological state by the encapsulated cells. We have developed an interfacial precipitation technique for encapsulating mammalian cells in polyacrylate membranes. This technique is based on the co-extrusion of a cell suspension and polymer solution through a concentric needle assembly and subsequent formation of a polymeric membrane around the cells in a precipitation bath. Here, we report a summary of our experience with the performance of the encapsulated cells in hydroxyethyl methacrylate-methyl methacrylate (HEMA-MMA) microcapsules.