Betaine Combined with Membrane Stabilizers Enables Solvent-Free Whole Blood Cryopreservation and One-Step Cryoprotectant Removal

Cryopreservation of red blood cells (RBCs) is fundamentally important to modern transfusion medicine. Currently, organic solvent glycerol is utilized as the state-of-the-art cryoprotectant (CPA) for RBC cryopreservation. However, glycerol must be removed before RBC transfusion to avoid intravascular hemolysis, via a time-consuming deglycerolization process with a specialized equipment (e.g. ACP215), thus limiting the clinical use of frozen RBCs. Herein, we report novel biocompatible CPA formulations combining zwitterionic betaine with membrane stabilizers (disaccharides or amino acids), which can achieve outstanding efficiency for RBC cryopreservation directly using whole blood without any separation process. Most importantly, due to the osmotic regulation capacity of betaine, a simple and fast one-step method can be used for CPA removal, which is significantly superior to current multi-step deglycerolization process. This work offers a promising solution for highly efficient and solvent-free RBC cryopres...