Reliable cytotoxicity experiments - (Sep/25/2005 )
Has anyone used Promega´s CellTiter 96® AQueous One Solution Cell Proliferation Assay? I have tried to measure the cytotoxicity of my protein and I get the same level of absorbance in both control and transduced cells approx. 0.25. However, when I treated the cells with drugs (just to test the functionality of the kit), the absorbance was under 0.1. So, the kit seems to work, however what I wanted to ask..is the level of my absorbance high enough? And how do you present your results in general? As percentages or absorbances?
In my view the level of absorbance in very low, i generally incubate plate untill i get an OD of >0.5, and regarding the presentation, percent cytotoxicity is a ideal choice
An absorbance of 0.25 is on the low end for the assay - I usually aimed for an Abs. of about 1 when I used MTS/PMS. What is your cell density? And how long are you incubating with the MTS? I reccomend going right up to the maximum suggested (4 hrs I believe).
Some cells just don't work very well in the MTS assay - the key rxn relies upon a dehydrogenase to form the formazan (brown stuff). I know one of my cells just wasn't very goood upon carrying out this reaction.
Anyway, MTS is a pain in the ... uh, well it's annoying. Have you tried Cell-Titer Blue? Also from Promega. If you have a fluorescent plate reader it's a bit less goofy in the results.