Simplified Method of Making Alginate-polylysine Microcapsules for Hybridoma Cell Culture Using Rpm1 1640 Medium

Among various efficient cell culture systems, the encapsulation of living cells within alginate-poly-llysine (PLL) membrane has received much attention as a means of improving the production of desirable cellular products. This method, which was successfully demonstrated by Lim and Moss in 1979, was primarily developed to transplant living cells without an in oivo rejection reaction (Lim and Sun, 1980; Lim and Moss, 1981). Damon Biotech has employed this process (ENCAPCEL) to grow a number of cell types including hybridoma cells and genetically engineered cells and has shown that microencapsulation of hybridoma cells has advantages in production and purification of monoclonal antibodies (Rupp, 1985; Posillico, 1986; Nilsson, 1987). Overall, the microencapsulated cell system has several advantages when compared to a free cell system. First, microcapsules are much larger than free cells and their use in perfusion systems is much easier. Second, direct sparging of gases into a bioreactor is permitted since cells are protected from physical shear inside microcapsules. Third, the product can be partitioned into either the microcapsules or the medium. However, the current technique of producing the microcapsules is complex and it involves many steps: the formation of alginate beads, treatment of PLL, liquefaction of the inner core of the alginate beads using citrate buffer and several washing steps (Lim and Sun, 1980; Lim and Moss, 1981; Lim, 1984; Goosen et al., 1985). In this article, we show that this method can be simplified by cultivating cells in RPM1 1640 medium which is one of the typical basal media (Adamson et al., 1987).