Algorithm optimization of cryopreservation protocols to improve mesenchymal stem cell functionality

Cryopreservation of Human iPS Cell Aggregates in a DMSO-Free Solution—An Optimization and Comparative Study

“…Compared to our previous DE algorithm studies (Pollock et al, 2017;Pi et al, 2019a), this study optimized four variable components instead of the former three variables, which resulted in six times as many possible vectors in the parameter space than before. However, the population size of each generation (i.e., 10) was smaller than what had been commonly used before (i.e., 13-27).…”

“…A DE algorithm with the basic mutation strategy (DE/rand/1/bin) (Storn and Price, 1997;Pollock et al, 2017;Pi et al, 2019a) was used to rapidly optimize the composition of the DMSO-free freezing solution for hiPSCs based on the functional metric of post-thaw reattachment rate. Briefly, the DE algorithm utilizes stochastic direct search to randomly generate an initial group (Generation 0) of sample parameters (i.e., concentrations of DMSO-free CPA molecules) from the population spanning the entire parameter space.…”

“…DMSO-free CPAs have the potential to alleviate the aforementioned pain points and improve the utility, effectiveness and efficiency of hiPSC cryopreservation. We have demonstrated in previous studies that combinations of sugar, sugar alcohols and amino acids can be used to preserve human mesenchymal stem cells and T lymphocytes (Pollock et al, 2016(Pollock et al, , 2017Pi et al, 2018Pi et al, , 2019b. When used to cryopreserve cells in vitro, they have been shown to act in concert with each other and amino acids to protect and stabilize cells (Pollock et al, 2016;Pi et al, 2019b).…”

Preservation of cell-based immunotherapies for clinical trials

“…The window of manufacturing both pre-freeze and post-thaw can be influenced by biochemical toxicity. For example, the duration that cells are exposed to DMSO-containing cryopreservation solutions is limited to short times pre-freeze and post-thaw [6]. This restriction complicates the workflow considerably at both the site of manufacture and the site of use.…”