Use of Directional Solidification to Quantify the Thermophysical Properties of DMSO-based Cryoprotectant Solutions

Cryopreservation using freeze–thaw methods is one way in which cells can be safely stored at low temperatures for indefinite periods of time. Unfortunately, the process itself can damage the cells such that the number of viable cells after thawing is reduced. This problem is particularly important when dealing with nonproliferating cells, such as primary hepatocytes. In the current study, directional solidification is used to help improve success when cooling hepatocytes to subzero temperatures. Specifically, by analyzing the crystallization of solutions, cell suspensions, and tissue cultures in the presence of dimethyl sulfoxide (DMSO), we determine how changes in the morphology and rate of crystal growth influence cell survival. The results demonstrate that the presence of extracellular matrix (ECM) and alterations in DMSO concentration are two ways to affect cell viability. Next, by modeling the directional solidification results as a Stefan–Neumann Problem, the image analysis data is then used to quantify the solid thermal conductivities of various DMSO solutions.