PEG-based Polyampholytes as Osmotic Stabilizers during Cryopreservation of Living Cells

Improved cryopreservatives are necessary to enable complete recovery of living cells and tissue after frozen storage. A key challenge in cryopreservation is osmotic stress on cells as extracellular solutes become concentrated when water freezes. Herein, we synthesized a new class of polyether-based polyampholytes capable of reversibly binding dissolved salt ions. We hypothesize that these polymers act as “osmotic buffers” that stabilize osmotic pressure during freezing and thawing of living cells. Excellent biocompatibility was demonstrated, and cryoprotective ability was evaluated for each material. Salt-binding behavior was studied through conductimetric and calorimetric techniques. Finally, we employed the high compositional tunability of these PEG-based polyampholyte materials to examine the effect of charged group structure on salt-binding and cryoprotection.