transfection with lipofectamine 2000 advice - (Aug/30/2013 )

Hi, 

I have carried out a transfection with lipofectamine 2000 by invitrogen today. 

I always add lipofectamine to my sample tubes under the hood, however by mistake I have added it on the bench today.

I am wondering if that would have contaminated the whole tube of lipofectamine that I am currently using?

Thanks

It depends. If you don't see contamination of your cells in a few days, your reagent is still OK. 

thank you, is there any easy way i can test the reagent itself to see if it got contaminated?

You can try adding a small amount of the reagent to a volume of media (no cells) and incubate it for a day or so at 37 degrees, then just take a look at it under the microscope.

Bacteria and fungi tend to grow explosively enough that even a small amount will make themselves evident after a few hours this way.  You can have cases however where the antibiotics in the media strongly inhibit bacterial growth without actually clearing them, in which case it can take a while for contamination to be really apparent.

This also won't rule out more subtle contaminants like mycoplasma, which you'd need a mycoplasma testing kit for.

Thank you for the suggestion, I might  try it on Monday. Would you recommend getting a new lipofectamine for future experiments, or should I try to test if it did get contaminated first?