We have been vocal, on this blog and elsewhere, about the importance of improved cryopreservation solutions and techniques. Oftentimes, optimization procedures start from what has been the most widely-reported drawback of traditional cryopreservation approaches: the toxicity of the CPAs typically used. For that reason, various DMSO-free solutions have been developed (Akron has been pioneering in that area with our line of DMSO-free media optimized for different cell types), as well as new approaches, which include vitrification and hypoxia.
Such approaches are welcome as they collectively contribute to our understanding of the techniques that can be adopted to improve this important task. Dr. Adam Higgins, professor at the School of Chemical, Biological and Environmental Engineering at Oregon State University, and his colleagues published a new report which introduced a new paradigm for developing cryopreservation approaches.
Starting from the assumption that traditional cryopreservation is based on toxic CPAs, that are considered such due to temperature and concentration, and results in low viability, the authors developed a mathematical optimization algorithm to design procedures for addition and removal of glycerol. In a previous report, they had described the algorithm, while in this publication they tested and demonstrated its utility in a real laboratory setting.
They discovered that bovine pulmonary artery endothelial cells responded very well to their approach.
Based on their algorithm, they found that the optimal temperature for CPA loading was 37°C and the optimal temperature for exposure the final vitrification solution was 4°C.
This yielded a yield of approximately 80% cells, obtained with an exposure of the cells to a concentration of 55% v/v glycerol, whereas conventional multistep techniques resulted in only 10% cell yield.
A successful result, and one that illustrates, once again, that cells favor environments that address aspects of the preservation workflow that go beyond composition of the CPA.