Carboxylate-functional Poly(methyl glycidyl sulfoxide) Synthesis and Applications in Cryopreservation

Cryopreservation enables the possibilities of biological and medical applications such as organ/blood transplant, in vitro fertilization, endangered plant tissues, animal oocytes and semen preservation. However, it is also a practice facing many challenges such as ice nucleation and recrystallization upon thawing and the cytotoxicity nature of cryoprotectants that negatively impact the vitality of cells. Of all cryoprotective agents, polymers are historically proven to be one of the most versatile and advantageous materials due to their high molecular weight. In this study, a carboxylate-functional poly (methyl glycidyl sulfoxide) (PMGS) was synthesized and studied, aiming to lower the cytotoxicity. However, post-thaw cell metabolic activity of 20% and 30% carboxylate content anionic-functional PMGS is very similar to that of the regular PMGS, at 30% relative cell activity. Furthermore, ice nucleation was studied by designing a water-in-oil emulsion to eliminate the effect of impurities acting like ice nucleating agent (INA) and achieve near homogenous ice nucleation in cryopreservation. The images acquired on the optical microscope were analyzed in combination with the w/o emulsion design to provide a foundation for the most optimal testing environment of a new polymeric cryoprotectant.