I hadn’t read about Isochoric preservation before:
The idea of isochoric preservation is to enclose the biological matter (cells, tissue, organ) as well as an ice crystal in a sealed container called a pressure vessel (figure 15) containing a fluid. The isochoric chamber is placed in a bath at constant temperature. The system is therefore in a thermal equilibrium. The chamber is hermetically sealed so that the volume is constant. Once the biological matter is introduced in the chamber, it is placed in the bath, and the temperature of the system decreases. The temperature of the bath is set to the phase transition temperature of the liquid in the chamber. At this temperature, the ice crystal placed in the chamber will trigger nucleation, and consequently, ice will form around the ice crystal. This crystal has to be placed strategically: far from the biological matter, so the ice formed around will not reach it (Rubinsky et al., 2005). This process is summarized in figure 16. The temperature has to be kept constant so that equilibrium is reached: the ice formed does not grow too much.
The point of this procedure is that the nucleation site present at the bottom of the vessel (in figure 16) will inhibit the formation of ice in the biological body by inducing ice formation around itself. As a result all the ice will form at this site, and none will form in or near the biological matter.
...Szobota and Rubinsky showed that when an idealized system is cooled until about − 109°C, nucleation is not observed because of the effects of pressure; this temperature would be somewhat higher in a regular biological system. Therefore, using an isochoric system could be advantageous for vitrification purposes.
I hadn’t read about Isochoric preservation before: