Culturing of BHK-21 cells in a medium, containing adult bovine serum after treatment with hydrophilic silicon particles

Abstract

Summary. The lipid concentration in adult bovine serum (ABS) is 7.93 + 1.29 mM and in fetal bovine serum (FBS) 2.90 + 0.39 mM. A high lipid concentration in the medium reduces the tested cell culture parameters. When a culture medium for BHK-21 cells, containing FBS, has the same lipid concentration as a medium containing the same volume fraction of ABS, the cell density and protein synthesis after 7 days, are reduced by about 15%. However, the cell density and the protein synthesis, in this medium with FBS and additional lipids, are still about twice as high as in a medium with ABS. The hydrophilic silicon particles Aerosyl have a specific affinity for lipids. Incubation in suspension of ABS with 2.5 g Aerosyl 300/liter serum, before use in a culture medium, yields a maximal increase of the cell density of BHK-2t cells and protein synthesis. However, after this incubation, the lipid concentration in ABS is still 2.40 + 0.71 times higher than in FBS. Some other materials (gels) remove lipids from ABS, but do not yield an increase of the cell density and protein synthesis, comparable with ABS treated with Aerosyl 300. These observations indicate that, besides lipids, Aerosyl 300 also removes other components from serum. Presumably some of these removed components inhibit cells in culture and others are essential for cells in culture. This is supported also by the observed maximal stimulation of cell in culture in a medium with FBS, treated with 2.5 g Aerosyl/liter serum.