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floating THP-1 cells - medium change advice - (Sep/20/2010 )


I was adamantly asked to culture THP-1 cells and did so, by thawing a cryovial and seeding the cells in a 25 cm flask. 3 days later 99% of cells are floating, which I reckon is OK. Isn't it?

So, do I need to change the medium before they reach ~8x 10^5 cells/ml and are ready to be passed? Since these are floating cells, how do I do that?

Also, would a 1/3 split ratio be OK for these cells?

Thank you very much,



Dear Victorius,

Just remove the cell suspension into a centrifuge tube and spin at 100g for 5 minutes. Remove the supernatant, being careful not to disturb the cell pellet. Add fresh growth media and gently resuspend the cell peelet so that you have a single cell suspension. If you want to do a 1:3 split then divide your cell suspension evenly between 3 x T25 cm flasks or just put all the cells into a T75cm flask......i.e. a 1:3 split.

Hope this is useful.

Uncle Rhombus


Dear Uncle Rhombus,

Thanks so much, that helps a lot.