Microencapsulation of mammalian cells in a hydroxyethyl methacrylate-methyl methacrylate copolymer: preliminary...

Erythrocytes were microencapsulated in a thermoplastic copolymer of poly-2-hydroxyethyl methacrylate (79% mole%) - co-methyl methacrylate (21 mole %) with little apparent initial cell lysis. Droplets of cell suspension and polymer solution were blown from the tip of a coaxial needle assembly into a receiving bath of hexadecane over phosphate buffered saline (PBS) containing a low concentration of nonionic surfactant. Capsules were trapped at the hexadecane/PBS interface where they were cured by the removal of polymer solvent to precipitate a polymer coating around the cell suspension. Important principles which were considered in the development of the successful process, included the need to prevent intermixing of polymer solution and cell suspension, to fully surround the cells with polymer solution prior to precipitation, and to prevent direct mixing of the curing bath with the polymer solution.