I am trying to setup dHL-60 Migration, using chemoattractant as fMLP! But, it is very difficult to find a good fold change. Even though I am getting atleast 2 fold some tims, but it is not always repetitive.

I tried

1) fMLP (1uM-1nM) , stock is in DMSO and further dilution is in media

2) starvation of cells

3) different micron insert.

But nothing worked. Could any one please suggest the unseen step, which might make a miracle in the experiment.

Thank you.