Hi guys,

I will stably transfect HEK293 cells and TSA201 cells. I am doing Geneticin death curves on both untransfected cells to determine which concentration to use for selection. The concentrations I am trying are from 0.4mg/ml to 2mg/ml. Now it is day 5, I don't see any cell death even at 2mg/ml geneticin. I also have a seperate dish of HEK293, which is culturing at 1mg/ml geneticin. Now it is day 9 and cells are grow happily. If my geneticin is good, I should be able to see at least some cell death, right? I am not sure whether my geneticin is bad or I use it in a wrong way.

My geneticin was ordered from Invitrogen in solution at 50mg/ml. Right after I received it, I started to use it in my culture as I mensioned above. Then I aliquoted them into small tubes and store in -20C degree. I added geneticin to complete DMEM medium, which contains 10% FBS, P/S. Is it possible that there is something in my DMEM (from Invitrogen too) inhibit geneticin? When do you guys usually start to see cell death with geneticin?

Any comment will be apprecated.

We found that at times geneticin in solution loses activity. So after wasting a lot of time and geneticin (we were fed up trying from various sources), we ended up making our own geneticin from powder which seems to work.

Thank you, scolix. I am thinking of geneticin powder too. Could you please tell me where you get the geneticin (which is working) from? If you have the product catalog number, that will be very helpful. Thanks again.

345810 , Calbiochem

Thank you, scolix. I have just ordered some from Calbiochem. Hope it will work this time.

geneticin is sensitive and instable towards UV-light, so protect it from day light

Thank you for you reminder, The Bearer.