I dissolve my drug in dmso so I need to add dmso to the control group to exclude its effect. Is 1% dmso save to cell? I try to dissolve my drug in 1% DMSO but still need to find solution to dilute DMSO in.
Probably depends on the cell type you are using. But for Caco-2 cells, 1% DMSO would work OK in terms of maintaining tightness/low cytotox measured in the MTT assay. Your control should have the same percentage of DMSO as the drug solution, but otherwise be similar.