Complete Growth Medium
Base medium: Combine 14.8g/L Dulbecco's modified Eagle's medium and Ham's F12 base (Sigma, D-9785), 1.2g NaHCO3 (Sigma, S-5761), 0.365g L-glutamine (Sigma, G-3126), 0.059g L-leucine (Sigma, L-8912), 0.0912g L-lysine (Sigma, L-8662), 0.017g L-methionine (Sigma, M-5308), 0.0612g MgCl2.6H2O (Sigma, M-1028), 0.0488g MgSO4.7H2O (Sigma, M-3409), 0.006g CaCl2.2H2O (Sigma, C-8106), and 0.0086g Phenol Red (Sigma, P-3532). Fill to 1L with Ultrapure Cell Grade water (ATCC® 30-2205). Stir to dissolve. Adjust pH to 7.1 – 7.3. Filter-sterilize using a 0.22 µm filter. Complete growth medium: Combine base medium with 20 ng/mL epidermal growth factor (Sigma, E-9644), 100 ng/mL cholera toxin (Sigma, C-8052), 0.01 mg/mL human insulin (Sigma, I-2643), 500 ng/mL hydrocortisone (Sigma, H-0888), and 5% Chelex-treated horse serum.
Volumes used in this protocol are for 75 cm2 flask; proportionally reduce or increase amount of dissociation medium for culture vessels of other sizes.
- Remove and discard culture medium.
- Briefly rinse the cell layer with 0.25% (w/v) Trypsin- 0.53 mM EDTA solution to remove all traces of serum that contains trypsin inhibitor.
- Add 2.0 to 3.0 mL of Trypsin-EDTA solution to flask and observe cells under an inverted microscope until cell layer is dispersed (usually within 5 to 15 minutes).
Note: To avoid clumping do not agitate the cells by hitting or shaking the flask while waiting for the cells to detach. Cells that are difficult to detach may be placed at 37°C to facilitate dispersal.
- Add 6.0 to 8.0 mL of complete growth medium and aspirate cells by gently pipetting.
- To remove trypsin-EDTA solution, transfer cell suspension to centrifuge tube and spin at approximately 125 x g for 5 to 10 minutes. Discard supernatant and resuspend cells in fresh growth medium. Add appropriate aliquots of cell suspension to new culture vessels.
- Incubate cultures at 37°C.
Subcultivation Ratio: A subcultivation ratio of 1:2 is recommended
Medium Renewal: Every 2 to 3 days
Note: For more information on enzymatic dissociation and subculturing of cell lines consult Chapter 10 in Culture of Animal Cells, a manual of Basic Technique by R. Ian Freshney, 3rd edition, published by Alan R. Liss, N.Y., 1994.
Complete growth medium supplemented with 5% (v/v) DMSO. Cell culture tested DMSO is available as ATCC Catalog No. 4-X.