Can I use RNAiFect for co-transfection of plasmid DNA and siRNA?
FAQ ID -515

No, we do not recommend to use RNAiFect for the transfection of plasmid DNA. The RNAiFect Kit does not contain Enhancer which is necessary to form condensed complexes before transfection of DNA into the cell. TransMessenger Transfection Reagent would be the right choice as it allows co-transfection of siRNA and plasmid DNA. Access the protocol via the following link: Co-transfection of adherent cells with siRNA and plasmid DNA using TransMessenger Transfection Reagent

Alternatively, you can use the Attractene Transfection Reagent with the QIAGEN Protocol "Fast -Forward cotransfection of adhernet cells with siRNA and DNA in 24-well plates using Attractene Transfection Reagent".