1 reply to this topic

[ecgian]

Hello,

I have a question about cryopreserved cells. I froze down HEK293T cells using DMEM (with 10% FBS) + 10% DMSO. After detaching them from the flask, I pelleted the cells and resuspended the cell pellet in 2mL of freezing medium and transferred 1mL cells into each cryovial. I first put them into -80C, and after a few days transferred them to liquid nitrogen. When I went to go put them in liquid nitrogen, I noticed that the color of the frozen stocks was orange. I was wondering if anyone could tell me why this is and if this is a problem? Will I have a problem when I go to thaw these vials of cells and use them?

Thank you.

[gfischer]

ecgian, on Dec 22 2009, 09:24 AM, said:

Hello,

I have a question about cryopreserved cells. I froze down HEK293T cells using DMEM (with 10% FBS) + 10% DMSO. After detaching them from the flask, I pelleted the cells and resuspended the cell pellet in 2mL of freezing medium and transferred 1mL cells into each cryovial. I first put them into -80C, and after a few days transferred them to liquid nitrogen. When I went to go put them in liquid nitrogen, I noticed that the color of the frozen stocks was orange. I was wondering if anyone could tell me why this is and if this is a problem? Will I have a problem when I go to thaw these vials of cells and use them?

Thank you.

Color change of the suspension is most likely due to a pH change.  It's not an infrequent occurrence; I wouldn't worry.