Study of physical processes occurring in serum-containing and polymer-based serum-free cryoprotective media

Abstract

To investigate the mechanisms of cryoprotection with compositions that were supplemented with polymers (dextran [Dex], hydroxyethyl starch [HES], polyethylene glycol [PEG]) or fetal bovine serum [FBS]). Methods. Differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) of cryoprotective media containing serum, as well as media that do not contain serum or its components but include polymers. Results. The combinations of dimethyl sulfoxide with FBS or polymers in cryoprotective media were able to promote the formation of amorphous phase and suppress salt eutectic crystallization/mel ting and recrystallization.The medium supplemented with 0.7 M Me 2 SO and 100 mg/ml Dex (0.7Me 2 SO+Dex) was somewhat superior compared to other compositions. It also had an optimal glass transition temperature (-26…-21 °C). The feature correlated with an adequate cell recovery when the medium was utilized to preserve testicular cells. Conclusions. The mechanism of cryoprotection depends not only on the concentrations of cryoprotective agents such as Me 2 SO, polymers or FBS, but also on the composition of the cryoprotective media. The 0.7Me 2 SO+Dex medium can be the basis for the creation of commercial serum-free cryoprotective media with a defined stable composition that does not require removal of Me 2 SO before using the cryopreserved cells or tissues for cultivation, transplantation and transfusion.