Beware of the secret cell killer for samples in cryogenic storage.
Timing is crucial. Never has this been more accurate than when transferring samples from cryogenic storage.
Even momentary warming events can occur in product handling and do damage to cells without notice – which is totally alarming but entirely preventable. Here’s how: STAY AWAY FROM DRY ICE.
The cryogenic cold chain is getting more and more attention with the increasing focus on regenerative medicines that absolutely require cryogenic temperatures to maintain shelf life.
In fact, hBM-MSC stored at -190°C that briefly crosses the glass-transition temperature (Tg-H2O, approximately -135°C) shows reduced recovery, viability, and proliferation compared with a control group that did not warm to Tg.
For this reason, every measure should be taken to prevent transient warming events that can happen almost secretly. The biggest opportunity to decrease these warming events is: KEEP CRYOGENICALLY FROZEN SAMPLES AWAY FROM DRY ICE.
There, we said it again.
The reason for the warning is simple: Dry ice can warm cryogenically stored samples TWICE AS FAST as ambient temperatures.1
Ian Pope, Senior Director and General Manager Cryo Solutions Group at Brooks Life Sciences, puts it in clear terms.
“One thing people don’t think about is that dry ice is 100 degrees warmer than the sample they are putting in it,” he explained.
“Combine that with the sublimation of the dry ice, and you can get a warming effect two to three times greater than what you would experience by simply placing your tube on a bench,” he continued. “The thermal equivalent would be like putting a hair dryer on top of an ice cube…or dropping the same ice cube into boiling water.”
One best practice to reduce transient warming events above and below Tg is to handle cryogenic vials in an environment under -150°C. Handling samples once they have been removed from any tank should happen with the CryoPod™ or other calibrated sub -150°C carrier.
Take further protective measures with an automated freezer environment like BioStore™ III Cryo -190°C System that offers multi-user access control, chain-of-custody tracking, and sample retrieval – all in under 60 seconds. Now that’s timing!
1. Salvetti, M., Fink, J. Barlett, A., Stira, M., Warhurst, J. Thermal excursions of cryogenically frozen vials (below -150°C) and the risk of rising above Tg: analyzing warm-up rates from cryogenic storage to both dry ice and ambient temperature environments. Link