Implantable biocompatable immunoisolatory vehicle for delivery of selected therapeutic products

An implantable immunoisolatory vehicle for providing a biologically active product or function to an individual, the immunoisolatory vehicle comprising:

• (a) a core comprising a volume in excess of 1 .mu.l and at least 10.sup.4 living cells dispersed in a biocompatible liquid, said cells being capable of secreting a selected biologically active product or of providing a selected biological function to an individual;
• and
• (b) an external permselective jacket surrounding said core, said jacket being greater than 5 microns thick and formed from a hydrogel that does not tonically bond to a polymer of opposite charge on the core during formation of the jacket, said jacket being free of said cells projecting, externally therefrom, said jacket being biocompatible and having a molecular weight cutoff permitting passage of molecules to and from the core through said jacket to provide said biologically active product or function.