Hydrogel Microencapsulation Enhances Cryopreservation of Red Blood Cells with Trehalose

Cryopreservation of red blood cells (RBCs) plays a vital role in preserving rare blood and serologic testing, which is essential for clinical transfusion medicine. The main difficulties of the current cryopreservation technique are the high glycerol concentration and the tedious deglycerolization procedure after thawing. In this study, we explored a microencapsulation method for cryopreservation. RBC-hydrogel microcapsules with a diameter of approximately 2.184 ± 0.061 mm were generated by an electrostatic spraying device. Then, 0.7 M trehalose was used as a cryoprotective agent (CPA), and microcapsules were adhered to a stainless steel grid for liquid nitrogen freezing. The results show that compared with the RBCs frozen by cryovials, the recovery of RBCs after microencapsulation is significantly improved, up to a maximum of more than 85%. Additionally, the washing process can be completed using only 0.9% NaCl. After washing, the RBCs maintained their morphology and adenosine 5'-triphosphate (ATP) levels and met clinical transfusion standards. The microencapsulation method provides a promising, referenceable, and more practical strategy for future clinical transfusion medicine.