Answer by Dr. Jessica Wagener, Application Specialist Cell Handling at Eppendorf
This article appeared first in “Inside Cell Culture” , the monthly newsletter for cell culture professionals
DMSO (Dimethyl Sulfoxide) is a polar, aprotic organic solvent that is commonly used as a cryoprotectant because of its membrane penetrating and water displacement properties. It is added to cell culture media to reduce ice formation and thereby prevent cell death during the freezing process.
Empiric studies report that during an initial freezing phase a temperature reduction of about 1°C/min is optimal. In vitro, DMSO at concentrations higher than 10% (v/v) is reported to induce membrane pore formation and apoptosis through caspase-9 and -3 activation. The response will depend on the type of cell or cell line.
Time is thus a critical factor when you freeze and thaw cells, because you want to minimize their exposure to DMSO. A trypan blue test can help to detect the cells' viability after thawing.
Hematopoietic cells, embryonic stem cells and many hybridoma cell lines seem to be particularly vulnerable to DMSO, as it is also a differentiation inductor.