Hi David,

Cryoprotective properties of dimethylsulfoxide (DMSO) were well known as penetrating cryoprotective agent (Lovelock & Bishop, 1959).

However, it seems to be important to notice that the toxicity of the DMSO increases strongly with the temperature (above 10°C) and the time of incubation (or, at least, washing baths during the heating step following thawing) (Fleming & Hubel, 2006). Indeed, an incubation at room temperature during 15-45 min sems to be improperly long!

Moreover, at wich concentration of DMSO did you want to incubate your cells?

Thanks for the reply Ludovic.

Freezing medium is cold HSA + 10% DMSO. We are questioning whether a 15min incubation as recommended by NUNC (manufacturer of the Mr Frosty freezing containers) prior to transferring to -80 degrees, then liquid N2  would improve cryopreservation, or be harmful.