in vitro cell proliferation assay - use of the DMSO as drug solvents (very urgent) (May/26/2006 )
i am new to cell culture work. i have to study the cytotoxic effect of one drug in my cell lines. i will
be doing the MTT assay.
one thing which i am not able to understand that i saw in many papers that drug is dissolved in
DMSO. and it is also mentioned that " final DMSO cocentration in all assay did not exceed 0.15%".
this is not understood to me.
could please someone explain.
i will be thankfull.
waiting for reply.
It's because DMSO is toxic for the cells.
you should avoid to add too much DMSO, and you should also check that the DMSO you added has no effect on the cells.
Do you mean you don't understand about the effects of DMSO or that you don't understand what 0.15% means?
Missele has already answered the first point although I will add that DMSO is not necessarily toxic but acts as a potent cell differentiating agent which can cause problems.
If you don't get the 0.15% bit then this means v/v (volume-to-volume) i.e., for every 1 mL of liquid there are 1.5 µL DMSO and 998.5 µL of medium (or whatever).
So if you are culturing cells in 10 mL of medium you need 15 µL of DMSO and 9.985 mL of medium.
The concentration of DMSO in your cell culture should be low but I think you can even use more than 0.15% final concentration but the better is inded to do as described in that paper.
I would like to advise you to use the same final concentration of DMSO in all samples.
So in case you are exposing cells to a different concentrations of drug, you should prepare sequential dilutions of the drug, diluting the stock solution also in DMSO to get working solutions with different concentrations.
By having different working solutions, you can add the same volume of drug (same amount of DMSO) get different final concentrations of drug.
I am not sure if I made myself clear, if not please let me know and I can write an example.