Jacobs:Protocol Freezing and Thawing Cells
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Procedure
Materials for Freezing
- Trypsin
- Trypan Blue
- Hemocytometer
- Media for frozen cells
- DMSO
Freezing
- Check cell culture log and be sure there is room for frozen vials
- Label vials with cell type, date, passage number, etc.
- Collect cell suspension by trypsinizing
- Combine all flasks into 50 ml tube
- Count cells
- 1 million cells per vial (for MC=4 vials/flasks, for UMR=6 vials per flask.)
- 1-2 million cells per vial for MLO-A5
- Make fresh freezing down media
- General: 95% FBS + 5% DMSO
- MLOs: 50% α-MEM, 40% FBS, 5%DMSO
- Spin down the cell suspension and pellet the cells (1500rpm, 7-10 min)
- Aspirate media
- Resuspend cell pellet in freezing media
- Aliquot 1ml freezing media per 2ml tube
- Place tubes in round isopropanol box in -80C freezer OR
- Transfer to the -20C for 2-3 hours
- Transfer to the -80C for at least overnight
- Store permanently in liquid nitrogen within 1-2 days
- Be sure to record in the cell culture log where the cells are permanently stored
Thawing
- Setup two vials of cold (4 C) media (10 ml) in a 15 ml tube
- Warm remaining media (~5-8 ml) in a 15 ml tube to 37C
- When ready to thaw, remove vial of cells from liquid nitrogen
- Swirl the vial in the water bath (37C) until a small ice chip is left in the tube (~1 min)
- Place the vial in the hood and clean it with 70% ethanol
- Immediately remove the contents of the vial and place into the cold media
- Rinse the tube down with some of the cold media from the second vial
- Spin down cells at 2000 rpm for 5 min
- Aspirate off the cold media and resuspend the cells in the warm media
- Transfer the cells and the media to a T25 (or T75 depending on the number of cells)
- Count cells
- Place in incubator
- Change the media once the cells have attached to the plate
- Allow cells to grow to 80-90% confluency
- Split cells (1:3) into T75 flasks
- Continue to split cells and freeze down as needed
References
Contact
- History: CMBL – CRJ/JJR, last updated 8/1/07
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