Journal: bioRxiv

Article Title: Physical vitrification and nanowarming at human organ scale to enable cryopreservation

doi: 10.1101/2024.11.08.622572

Figure Lengend Snippet: Liter volumes of a CPA (0.5-3L) 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.

Article Snippet: A 3D CAD geometry of a cryobag filled with CPA was created and simulated in COMSOL for heat transfer simulations (Fig. S2).

Techniques: Crystallization Assay, Convection, Recrystallization

Journal: bioRxiv

Article Title: Physical vitrification and nanowarming at human organ scale to enable cryopreservation

doi: 10.1101/2024.11.08.622572

Figure Lengend Snippet: a Schematic for a representative case, 0.5 L cryobag containing CPA with placement of three fiber optic temperature probes (3 cm apart). Blue arrows show the direction of LN2 flow in CRF. b Experimental and predicted temperature vs. time plot for 0.5L M22. The dashed green line shows the programmed CRF temperature profile/protocol. c CRF cooling protocols for 0.5, 1, and 3 L volumes. The regions of ice formation and fracture danger are labeled. Scatter plot of d center cooling rate and e temperature difference (ΔT max in the glassy region) for all three volumes tested for M22 (mean ± SD; n=3). Cooling rate is calculated in ranges 0 to -100 °C and -120 to -150 °C for temperature difference plots. Mean cooling rates are greater than the CCR of M22 (∼0.1°C/min). Temperature differences are within the allowable limit (dashed) (< 20°C) calculated from a simple thermal shock equation .

Article Snippet: A 3D CAD geometry of a cryobag filled with CPA was created and simulated in COMSOL for heat transfer simulations (Fig. S2).

Techniques: Labeling

Journal: bioRxiv

Article Title: Physical vitrification and nanowarming at human organ scale to enable cryopreservation

doi: 10.1101/2024.11.08.622572

Figure Lengend Snippet: a Schematic showing 1L (left) and 2L (right) cryobag containing CPA with three fiber optic temperature probes (placed 4 cm apart / 13 cm depth inside 1 L and 15 cm depth inside 2 L cryobags). The dimensions of the cryobag are shown. b Temperature vs. time plot for rewarming of 1L and 2L volumes of M22 (differences in rates due to relative differences in IONP concentrations). Region with greatest risk of ice formation is shown as (*) and fracture failure as (**). Scatter plots of c average rewarming rate and d temperature difference (∆T) for 1 L and 2 L M22 (mean ± SD; n=3). The rewarming rate is calculated from 0 to -100°C. Average rewarming rates are greater than the CWR of M22 (∼0.4°C/min). Maximum temperature differences (ΔT between center and edges) are calculated between -120 to -150°C (the glassy region).

Article Snippet: A 3D CAD geometry of a cryobag filled with CPA was created and simulated in COMSOL for heat transfer simulations (Fig. S2).

Techniques: