I used polyethyleneimine for plasmid transfection into different cell lines, including Hek293, and I got excellent results. In addition, it was also inexpensive.

Hello Birgit! EXPI293 kit from Thermo is the most effective when you use Expifectamine 293 with enhancers (1 and 2) according to manufacturer protocol. I also recommend using Expi Medium. I tried many optional approaches using Expi293 cells, all of them decreased efficiency of protein production.

Hi,

I have used both cell lines but did not mix the systems. If HEK293F cells are your choice, I would follow the tip of @Niloufar Khakpour to use PEI - for us it worked with FreeStyle 293 Expression Medium from Thermofisher. However, we got better results while using FreeStyle MAX reagent (as transfection agent) with Freestyle Medium.

Thank you very much for your experience and advice. Originally I had Expi 293F cells, but they didn´t grow well in the medium I used - The Hec medium we had around, which is why I considered swiching to Hec cells. @Krzysztof Mikolajczyk thanks for the hint concerning the medium. Once in Exoi medium, the Expi cells suddenly recovered splending and the protein production worked well. Thank you all for your support. I will keep it in mind for my future transfections.