4 replies to this topic

[mermaidlisa]

Hi,

I'm totally new with cell assay and not sure how "old" my caco-2 cells could be for MTT assay. Could someone please help me on this, or maybe show me where I could find the answer?

Thanks a lot  

Lisa

[bob1]

Passage number should not affect the MTT assay, so long as the cells have been passaged properly to keep them growing in the log phase (i.e. not over confluent).

[mermaidlisa]

bob1, on Feb 18 2010, 07:11 AM, said:

Passage number should not affect the MTT assay, so long as the cells have been passaged properly to keep them growing in the log phase (i.e. not over confluent).

thanks for your reply but could you elaborate more please? i'm a bit confused here...

i thought that selection occurs every time we subculture and cell functions will change significantly at higher passage number, hence cell viability of low- and high- passage is no longer comparable? please enlighten me >_<

[bob1]

MTT is an end point assay that measures the ability of enzymes to metabolise MTT to form the purple formazan.  It should work irrespective of the passage number of the cells you are assaying.  So long as the treatment and control cells are of similar passage numbers, results from the MTT assay should be comparable.  I couldn't say if you could then compare these results with ones done on much earlier passage number cells.  If you want to know if you can compare, take some old cells and some new cells and put them through the same test at the same time.  If you get similar results between old and new, then  you can compare for that assay only... repeat for other assays.

[mermaidlisa]

bob1, on Feb 22 2010, 07:51 AM, said:

MTT is an end point assay that measures the ability of enzymes to metabolise MTT to form the purple formazan.  It should work irrespective of the passage number of the cells you are assaying.  So long as the treatment and control cells are of similar passage numbers, results from the MTT assay should be comparable.  I couldn't say if you could then compare these results with ones done on much earlier passage number cells.  If you want to know if you can compare, take some old cells and some new cells and put them through the same test at the same time.  If you get similar results between old and new, then  you can compare for that assay only... repeat for other assays.

Oh i get it now! Thanks a lot Bob