JetPEI transfection of insect cells

Getting DNA into cells is one of the basic requirements of most of today’s life sciences. There are many ways to get DNA into cells: More exotic methods include shooting and electric shocks, but the most common methods deploy chemicals called transfection reagents. These somehow mingle with the DNA and help it to cross the plasma membrane. PEI (Polyethylenimine) is one of the “cheaper” transfection reagents. If you make it yourself, it probably costs about the same as calcium phosphate transfection (which is one of the oldest and cheapest methods). Even commercially available preparations, such as JetPEI and PEIMax, are budget-friendly compared to many other transfection reagents. However, they do not work very well for insect cells. When I asked - perhaps ten years ago - our provider (Polyplus Transfections), they provided me with a custom protocol for the transfection of insect cells with JetPEI. I have been using it successfully, but mostly only to generate stable cell lines. When making stable transfectants, a somewhat lower transfection efficiency is acceptable. However, I could not find that protocol anywhere online, and thus I have attached it to this post for everybody who needs this information. In a nutshell, the amounts of DNA and transfection reagent are increased to make up for the lower efficacy.