I have to perform exposure of cell culture medium (only RPMI, not complete medium) to electric pulses in non sterile conditions, then I have to sterilize it for cell culturing. I cannot use filtration with 0.2 micrommeters pore size because I will lose some components, and I think that autoclavation will denaturate the medium properties. Do you have any other method to suggest? I also thought to use UV light exposure, but I don't know the right dosage to get sterilization without changing the properties of the medium.
Do you have any hint on this?
If you want to sterilise using UV, you need a sterile environment where you can put the RPMI in a thin layer and let it there at least 15 min with a UV lamp turned on, as is usually done when you sterilise the hood. If, by chance, you have access to a BIO SUN equipment (an UVA/UVB irradiation device) you could use it very well for this purpose (it has a dedicated program for sterilisation). Anyway, both UV sterilisation approaches presented here are time consumming, so I think what Thomas recommended you is the best way to solve your problem.
If there are no suspensions in the medium and it is clear filter like mentioned before. If you have a suspension, which sounds like someone has made this and it should be clear, then you might have made the medium incorrectly. If you are worried you will lose components via filtration there is no possibility of that at all. The filter is made to capture living organisms not small molecules. The smallest E. coli is about 1 um in length and 0.5 um in diameter so you can imagine how much smaller the components have to be. In fact the length of a carbon carbon bond is about 1.4 Angstroms, three orders of magnitude smaller than the cells and the filter holes.
Imagine yourself and something a thousand times bigger than you. If you are a 1 meter sphere then you could easily fall through a 1 kilometer hole. No way any small molecules are getting filtered out by that process.
Use filtration as Thomas suggested.
I'd clearly NOT recommend to sterilize your medium by UV treatment. There are components which are altered by UV irradiation (e.g. tryptophan), and depending on how you plan to use your medium for tests, this may affect results (compare to www.ncbi.nlm.nih.gov/pubmed/11460737). As long you did not add serum to your medium, sterile filtration is the method of choice here.
Edit: Altough I'm usually no fan of routine use of antibiotics, a standard mixture (e.G. Penicillin / Streptomycin) may be sufficient here. Just try to minimize contamination outside sterile environments by covering your vessels in between manipulations. But keep a keen look on still possible contaminations.
If concerned about media components binding to the filter. Filter a few ml of sterile 0.1% BSA followed by serval rinses with PBS. The BSA will bind to the filter and the PBS will remove any remaining BSA.
0.2 micron filter-sterilization is the best and viable method
Mohr gives you the good proposition, filtration on 0,2 µ is the method used if you prepare your medium from powder, but its easy if you used RPMI in liquid form and strerile from laboratory.
good continuation
Although I am not familiar with the cell culture medium, however, if the components can be separated, the heat-stable contents can be sterilized by autoclave and others by filtration, after that, mix the two media to get what you want.
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