The other transfection steps are the same as the operation of adherent cells. The difference is that when changing the medium, the cells are transferred to a sterile centrifuge tube, briefly centrifuged, the culture medium is removed, and fresh culture medium is replaced

First, I highly recommend to use RNAi Max lipofectamin, then lower media volume during transfection (400 ul/ well for 24 plate) and keep the cells in ATB free media 24 hours before and after transfection.

For siRNA transfection, Lipofectamine RNAi Max is much better and less toxic to the cells than Lipofectamine 3000, one of the main reasons as mentioned in the manufacturer instructions is that 3000 performs wide pores in the cell membrane that is why it is used in plasmid ( bigger size that siRNA) transfer to the cell.