A SIMPLE SERUM-FREE FREEZING MEDIUM FOR SERUM-FREE CULTURED-CELLS

Because the presence of serum in cell culture raises safety problems f or the production of biologicals, we have developed a serum-free mediu m (SFM) for the cryopreservation of animal cells. This medium is based on the SFM MDSS2, to which 10% dimethylsulfoxide (DMSO) and 0.1% meth ylcellulose or 3% polyvinyl pyrrolidone or no other additive than DMSO were added. Both, Vero and BHK-21 cells regularly cultivated in MDSS2 , could be cryopreserved in the three serum-free freezing media and co uld be thawed without any cell loss. No differences could be found bet ween the cells in the standard freezing medium (DMEM containing 10% fe tal calf serum and 10% DMSO) and those frozen in SFM, with respect to cell growth and viability. In the case of the Vero cells no difference s were observed with respect to their attachment. This medium represen ts the last step in fulfilling a complete serum-free animal cell based bioprocess.