Continuous Preparation of Immobilized Alginate Gel Beads Coated with Polyurethane for Mammalian Cells

Abstract

For the continuous preparation of alginate gel beads coated with polyurethane we used a device consisting of a vessel equipped with a double cylindrical nozzle. Alginate gels were formed in the vessel by introducing cell-alginate mixture into CaCl₂ solution. The gels slowly fell to the end of the inner nozzle, where urethane prepolymer (PU) was flowing in the outer nozzle for coating the gels. Addition of alumina powder into the cell-alginate mixture made it easy to prepare the immobilized gel beads on a continuous basis. Furthermore, the alumina caused desirable changes in structure of the gel matrix for growth of mouse hybridoma cells secreting antierythropoietin antibodies. Cell growth depended on characteristics of the PU used. PU with low content of isocyanate as a functional group helped to minimize damage to the cells. In addition, PU with high content of ethylene oxide (91%) was better for cell growth and antibody production than that with less ethylene (57%).