Process and system for producing biological materials from encapsulated cells

Cells (10) which produce a substance of interest are encapsulated within semipermeable membranes (12) having an upper limit of permeability sufficient to allow traverse of ions, amino acids and other cell nutrients (20) and then suspended in a culture medium containing these nutrients. Serum components (18) or other high molecular weight materials needed for ongoing viability and normal in vitro metabolism of certain types of cells may be included within the intracapsular volume and may be excluded from the extracapsular medium by limiting the permeability of the membranes (12). The substance of interest (22) to be harvested collects either in the intracapsular volume or the extracapsular medium, depending on the degree of permeability of the membranes and the molecular size of the substance.