Can Oligofectamine be used in this way? - (Oct/10/2009 )

I use Oligofectamine to transfect siRNA in 24 wells HeLa cells. In the application, I did some calculations and make a scale-up proportion. For example, it is suggested to dilute 3uL oligofectamine in 12uL Opti-MEM, while I mix 60uL oligofectamine in 240uL Opti-MEM and incubate for 5 minutes.

Once I performed this kind of mixture, I observed a big turbid white clump formed in the mixture (it looked alike fungus floating in media, you know. Please imagine ). Well, after 5 minutes incubation time, i re-suspend the mixture and mix with different siRNA. The transfection was not successful. No silencing was observed. This was repeated twice with same results. Alternatively, I have performed single mixture (3uL oligofectamine + 12uL Opti-MEM) for each and every reaction and they worked fine.

Does anybody have experience with this? I'm new to RNAi in my institute and nobody can be consulted

Well...after two and half months, this problem remained. I have purchased new Oligofectamine, try to dilute in DMEM (w/o serum) instead of Opti-MEM but the precipitate persisted. The only things I did not change are the pipette tips and eppendorf tube for mixing

Just want to get reponse from my dear forumer, does anyone observe such condition when using Oligofectamine? Or nobody encountered this problem before?

If I would like to change my transfection reagent, is there any recommendation? I'm transfecting siRNA into HeLa cells.

Thank you!