Fig. 1: Schematic flow of steps (left to right) in liter-scale vitrification and rewarming.
From: Physical vitrification and nanowarming at liter-scale CPA volumes: toward organ cryopreservation
Liter volumes of a CPA (0.5–3 L) in cryobags are large enough to hold a human organ. The cryobag is placed inside a controlled rate freezer (CRF) for cooling. For nanowarming (top section of the flow chart), the cryobag is vitrified with iron oxide nanoparticles (IONPs) suspended in the CPA. The vitrified cryobag is placed inside the RF coil, alternating magnetic fields are turned on, and the IONPs generate heat. This leads to successful (rapid, uniform) rewarming, avoiding crystallization or cracking failure modes even at the liter scale. Traditional rewarming employs convection using a water bath, which at these scales results in ice recrystallization and/or fractures due to insufficient rewarming rates (slow) and thermal stresses (non-uniform), respectively (lower section of the flow chart). IONP iron oxide nanoparticles, CPA cryoprotective agent, CRF controlled rate freezer.
