Quantitative measurement of cell-bubble attachment in bubble columns usingfoam flotation techniques

A simple and convenient system for quantitatively measuring the number of a dsorbed animal cells per unit of bubble surface area (Gamma, unit: cells/cm (2)) was developed. The system was successfully applied to recombinant Chin ese hamster ovary (r-CHO) suspension cultures to investigate the dynamic ce ll-bubble attachment in a bubble column. In serum-free medium, Gamma values increased with bubble rising height (H) and cell concentration (C) and the n became constant (about 1750 cells/cm(2)) when H and C were sufficiently h igh. In medium containing protective additives, the trends of Gamma values with H were similar to that in serum-free medium. Compared with serum-free medium, polyvinyl-pyrrolidone (PVP) increased the Gamma values to 1941 cell /cm(2) whereas other tested additives decreased the values of Gamma in some different degree.