Hello Sabah, could you please provide more info on your specific objective? do you want to have KO animals? do you try to produce a protein into a specific organ?
There are several possible reagents you can use, PEI-based or not.
if you want to deliver a plasmid into your mices, the only PEI-based reagent I know is JetPEI from Polyplus.
We, at Lipocalyx, have also PEI-based reagents but we are specialized for mRNA delivery. It means we can help you to get a very strong protein expression in a context of mRNA-mediated therapy, but not with DNA.