MTT Assay
Following transfection and a 48 hour incubation period, 10 µL of 5 mg/mL 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) solution was added to each well of cells and incubated for 4 hours at 37°C to allow proliferating cells to metabolize MTT into purple formazan. After MTT incubation, 100 µL of detergent (10% SDS in 0.01% HCl/water) was then added to the wells and incubated for another 2 hours at 37°C to release and solubilize the formazan. A sample of 150 µL from each well was then transferred to a clear 96-well plate and the absorbance at 570 nm was recorded. Raw absorbance values at 570 nm for each sample were then normalized to a non-transfected drug-free control sample to obtain a relative measure of cell metabolic activity.