How do I cryopreserve cells in a monolayer in the Petaka G3™, and why is it superior to standard freezing in cryovials?
Petaka G3™ is the only cell culture device that also allows for convenient and direct cryopreservation inside the primary culture device. Cryo vials feature a low surface-to-volume ratio. This means that the operator must use a slow freezing process while the glass transition progresses from the outside to the center of the vial. During this slow freezing period ice crystals may form inside of cells and damage them, leading to poor post-thaw viability. A preferred method is thin-film cryopreservation, only possible in the Petaka G3™. To freeze cells grown in a monolayer in the Petaka G3™ simply remove culture medium, rinse cells briefly in freezing medium, then aspirated out excess freezing medium. This leaves only a thin film of freezing medium over a layer of cells no more than 30um thick. This thin film may then be immediately flash frozen (vitrified) for permanent cryopreservation. This process prevents trypsin exposure, and all risks and damage associated with the traditional slow-freezing process.
To thaw vials, they must be warmed in an unsanitary water bath for 1-2 minutes. This poses a major risk to sterility and this extremely slow thawing technique leads to even more cell death. In contrast, thawing cells in a Petaka G3™ is achieved simply by filling it with warm medium. This means each cell thaws in less than a second as the warm medium covers the frozen cell; no water baths, running water, or sample transfers required. After adding warm medium, cells in the Petaka G3™ go directly to culture, with no reattachment time or trypsin damage.
Moreover, up to 25 million attached cells may be frozen in a single Petaka G3™, using just 1ml of residual freezing medium. This means that when 24ml of warm medium is added to a Petaka G3™, the standard 10%DMSO is diluted to around 0.4%. This level of DMSO is no longer damaging to cells in culture, so cells thawed in a Petaka G3™ never need to be spun-down or washed during initial recovery and incubation. Cryopreservation in the Petaka G3™ means the whole process is faster, easier, carries less contamination risk, and leads to much higher post-thaw cell viability.