CONTROLLED RELEASE USING MICROENCAPSULATED MAMMALIAN-CELLS

Mammalian cells have been encapsulated in a biocompatible, thermoplast ic hydroxyethyl methacrylate-methyl methacrylate copolymer by interfac ial precipitation. These microencapsulated cells constitute a novel fo rm of controlled release device in which the therapeutic agent (e.g., insulin, dopamine) is produced by natural or genetically engineered ce lls which are transplanted into a host, and isolated from the immune s ystem by the permselective capsule wall. Capsules were approximately 9 00-mu-m in diameter with an assymmetric, ultrafiltration-like membrane (approximately 90-mu-m thick). The molecular weight cutoff was approx imately 100 kD. Various cells (pancreatic islets, PC12 cells, MLA 144 lymphoma) have been encapsulated. At least some of the cells retain th eir viability as evidenced by functional assays (insulin or interleuki n 2 secretion) or by enzymatic assay. How the capsule wall affects cel l behaviour is the focus of current research.