Intracellular Ice Formation in Three-Dimensional Tissues: Pancreatic Islets

Abstract

The formation of ice within living cells during freezing is typically a lethal event. Design of optimal cryopreservation protocols therefore requires the ability to define the conditions under which intracellular ice formation (IIF) will occur. A model for IIF in cells was adapted to predict the probability of IIF in the multicellular pancreas islet during freezing, and experimental data were obtained via cryomicroscopy for a variety of freezing conditions. The influence of a cryoprotective agent, dimethyl sulfoxide (Me₂SO), on IIF was evaluated. The model was applied to evaluate the sensitivity of IIF to a number of key physiological and protocol parameters. Agreement between the model and experimental data for IIF in pancreas islets in 2 M Me₂SO is quite good for cooling rates of 2°C/min and higher and temperatures to - 50°C.