different serum - (Mar/13/2005 )

during a transfection does it affect my cells negatively if i use different serums in the various steps? i have seen that a cell line can use different serums.

thanks.

hi
usually, it's not recommended to use serum during transfection. Protocols tell that the mix of transfection should be dissolved in serum free medium whitout antibiotics. The mixture should be let 3 to 5 hours on cells. Then you can add a 2x serum medium on you transfection mix, or replace the mix by fresh complete medium.
If your cells are quite sensitive to the serum you use, i would not recommend you to change your serum. But if cells are quite independent of the type of seriuum you use, well, try it and tell us about your experiments...

Fred

i am new in this area. what is the difference between serum medium and complete medium?

thanks.

hi
serum free medium is a media delivered by your manufacturer that do not contain neither serum nor anibiotic.

I mean by complete medium a medium that contains serum 10% in most cases and eventually antibiotic (streptomicyn / penicilin). But peni/strepto are not always added depends on the cell in culture.

fred

well : by an example it may be more clear...

Let say that your mixture xas finally dissolved in 10 ml serum free medium.
After 3 or 5 hours you can :

add 10 ml of media containing 20%serum (twice the serum concentration ; that's why i said
2x serum medium a serum with double concentration a usually used in your experiments.

or

replace the 10ml of serum free medium mixture by 10ml medium containg 10%serum (1x serum)

In fact several transfection reagents can be used indifferently in complete medium or serum-free medium. Other reagents still advise to use only serum-free media. The important thing in either case as fred said is NEVER to used antibiotics during the incubation with the transfection reagent, as cells are really sensitive during that time and the presence of antibiotics can greatly increase cell death.
In case of using serum-free media, I believe that it is better to use an enriched medium such as Opti-MEM, instead of home-made serum-free media.
Cheers!

thanks all.