Figure 3.

Schematic of the proposed islet cryopreservation protocol. (a) Changes in concentrations of cryoprotectants in the cryopreservation solution over time. (b) Changes in temperatures of the cryopreserved sample over time of the cryopreservation (time of freezing is t = 0 min). Islets are preincubated in 200 mM trehalose at 37 °C for 6 h (trehalose is kept at stable concentration throughout the incubation). 45 min before the end of this incubation time, step-wise DMSO addition protocol is initiated and samples are frozen in a programmable freezer. Frozen samples are plunged into liquid nitrogen and stored in a liquid nitrogen dewar until thawing. Thawing is performed in a 37 °C water bath until sample reaches 0 °C and CPAs are removed using a step-wise protocol. Thawed islets are transferred into a fresh culture medium and can be cultured at 37 °C. CPA cryoprotectant, LN liquid nitrogen.