A common method used in almost every lab these days is transient transfection of cell lines followed by some form of output (Western blot, reporter gene assays, etc.). In a majority of cases, one wants the highest level of transfection possible with the lowest amount of cell death. Lipofectamine™ 2000 (LF2000) is a reagent that I have found fits exactly what I need. I have used LF2000 successfully with the following cell lines: HeLa, 293, CHO, U2OS, and C33A. I get consistent results using this lipid for my transfections.
Invitrogen has taken the time to optimize this reagent and the recommend protocol that they provide works very nicely as a starting point. However, with that said, I have found that in HeLa cells, the recommended amount of DNA and lipid kills the cells unless you start the transfection at 95% confluency. What I have found works better is cutting back the amount of DNA and amount of lipid. The recommended protocol for cells in 24-well plate states using 0.8 µg of DNA and 2.0 µl of lipid. I have found that 0.5 µg and 1.5 µl, respectively, works just as well, but with much less cell-death.
Also, Invitrogen has provided a database of different cell lines that have been successfully transfected with LF2000 as well as their other lipid transfection reagents. The database can be found in their Cell Line Database. Once there, you can do a search for your cell line of interest. It may take you some time to find the protocols. I have found the database not that organized and you may have to follow a few links to get to what you are looking for; however, in the end, it is still a good resource, especially if you are starting a new project with a new cell line.
I have also tested LF2000 against two other lipids. These lipids were the Lipofectamine™ LTX (from Invitrogen) and ExpressFect (from Denville). Transfections were carried out in 12-well plates using 1 µg of DNA and the appropriate amount of each lipid. The plasmid used expressed a recombinant tagged protein. After 48 hours, cells were checked for death and were immediately lysed in 500 µl of a standard lysis buffer. 1, 5, and 10 µl of extract from each transfection was combined with 5X Laemmli Buffer and electrophoresed into a 7% SDS-PAGE gel and transferred to PVDF membrane. The membrane was probed for GAPDH (loading control) and the recombinant protein. I found that LF2000 and Lipofectamine™ LTX worked at the same level with very little cell death. ExpressFect also showed very little cell death; however, less recombinant protein was expressed compared to LF2000 and Lipofectamine™ LTX suggesting a lower transfection efficiency.
In the end, I think LF2000 is a very good reagent. It is more expensive than other reagents. ExpressFect is about half the price, but the results do not look as good based on the experiment I tried. As such, to me it is not worth switching to save money when the efficiencies are lower.
Assistant Professor
Department of Biological Sciences
San Jose State University