Method for adapting cells to serum-free medium

PROCEDURE METHOD FOR ADAPTING CELLS TO SERUM-FREE MEDIUM 

When the serum lot and nutrient medium or balanced nutrient medium have been 

Maintain the cells in the serum lot and medium determined as optimal in the previous experiments. Grow the cells under these conditions until the same doubling time previously obtained in the old serum and medium is achieved. 

Reduce the serum concentration to 7.5% and passage the cells when stable growth kinetics at this serum concentration are attained. Then reduce serum to 5% and repeat the process. The cells should adapt easily to these serum concentrations. 

Transfer a portion of the cells to 2% serum. At this serum level it is harder for the cells to adapt. If the cells do not grow, try transferring a new aliquot of cells from 5% to 4% or 3% serum and/or try adding defined supplements (e.g. insulin). For more information on medium supplements, refer back to Types of serum-free media . At each step, when the cells have become adapted, freeze some of the cells. Freeze a larger stock of vials when the cells are adapted to 2% serum. Should problems arise later on, this is a good point to return to. 

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