DMEM Sterilization

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usdmailz
usdmailz's picture
DMEM Sterilization

Hi everyone,
Iam a novice to this field so my question might seem silly for you people but plz try to answer it.I was asked to sterilize the DMEM(dulbecco's modified eagle's medium)without using micro filters.I think we cant autoclave it cos there are aminoacids in it which are heat sensitive.Can any one of you help me out?

marcus muench
marcus muench's picture
I must say I've never heard

I must say I've never heard of such a request. Why can't you filter the medium???

You are correct in that autoclaving the medium would cause some of the componants to decompose.

There are a number of options, none of which are perfect, that I can think of.

First, you can prepare everything in the flow hood. Start with autoclaved or filtered water and then open the package of powder in the hood and mix. The powder is not sterile, but maybe its mostly sterile and if you add antibiotics you may get away with not filtering. You could also add fungizone to kill yeast etc, but it can have bad effects on your cells as well.

Otherwise, the only crazy idea I can think of is to sterilize the medium with sodium azide for a couple of days (?) and then dialyze against a large amount of DMEM without the azide. In theory, the contents of the dialysis tubing should be sterile. However, this is crazy, may not work, and wastes a lot of medium, so you better have a good reason.

If you try any of this remember to put a sample of the medium at 37
C without anitbiotics for a day or so to quickly and easily test if it is sterile. It's easier than finding out that it is not sterile when you've added your cells.

Let us know if any of this works for you, I'm curious myself of what you can get away with. I'm also curious as to why you can't use a filter.

usdmailz
usdmailz's picture
Thanx a lot for expressin

Thanx a lot for expressin your views.They were really good.Well it was a challenge posed to me by my Prof..Iam thinkin of using UV rays to streilize it but iam not sure if it gets sterilized n i also have doubts regardin the time of exposure.There's another way of usin gamma rays (Co-60)but gettin the isotope is very costly.So the challenge still remains........

usdmailz
usdmailz's picture
Thanx a lot for expressin

Thanx a lot for expressin your views.They were really good.Well it was a challenge posed to me by my Prof..Iam thinkin of using UV rays to streilize it but iam not sure if it gets sterilized n i also have doubts regardin the time of exposure.There's another way of usin gamma rays (Co-60)but gettin the isotope is very costly.So the challenge still remains........

marcus muench
marcus muench's picture
usdmailz wrote:Thanx a lot

usdmailz wrote:

Thanx a lot for expressin your views.They were really good.Well it was a challenge posed to me by my Prof..Iam thinkin of using UV rays to streilize it but iam not sure if it gets sterilized n i also have doubts regardin the time of exposure.There's another way of usin gamma rays (Co-60)but gettin the isotope is very costly.So the challenge still remains........

I know UV can damage some compounds in serum, I'm not so sure on the medium componants.

Gamma sterilzations has been used for even food items, but I'm not sure of the dose required.

Good luck, and write back with results.

jachmoody
jachmoody's picture
You might consider trying

You might consider trying Tyndalization--bringing the medium just to boiling temperature on threee successive days. You can find this procedure described on line or in micro texts because of it's historical significance. Any spores present will germinate and be killed in the next heating and the time frame doesn't permit new sporres to develope.

jim