SmartFreez has designed a new Isothermal Cryoshield format, for 0.5L bottles, to mitigate the risks related to pressure and air interfaces caused by freezing inside bottles.
Without the Isothermal Cryoshield the top of the liquid freezes rapidly, causing the pressure of the enclosed liquid domain to rise. The entrapped air bubbles and concentrated protein phase are therefore pushed trough the formed ice-crust, which fractures, causing a foamy mound-like structure at the top. The impact of this phenomenon has been correlated with bottle deformation and rupture and also with aggregation.
The Isothermal Cryoshield is designed to prevent early freezing and closure of the top interface, thus preventing the buildup of internal pressure and enabling the release or air bubbles. The Isothermal Cryoshield generates a completely ﬂat frozen interface (figure 1 on the right).
Fig. 1 – The performance of the devices was evaluated by performing a freezing run (at -80 ºC) with solutions containing 30 % sucrose. On the left is shown the result obtained without the Isothermal Cryoshield and on the right is shown the result with the Isothermal Cryoshield (evidencing the ﬂat interface). The freezer was a -80 ºC Sanyo MDF-U500VX.