I am using K562 cell line. Recently, I tried to transfect these cells with siRNA bought from qiagen (flexitube siRNA).
For optimization I used forward transfection method in twelve well plate. We used three different conc. of siRNA (25, 50 and 75 pM) and transfection reagent RNAiMax (1.5, 3 and 4.5 uL) per well, that mean nine different combinations. I harvested cells at three different time points 6, 12 and 24 hour and run RT-qPCR (so total 27 well). Unfortunately, there is no difference between any of the time point or any combination I tried. My question is, if it is normal to have such problem (as I was expecting at least some difference) to have no difference at all.