Cryopreservation of red blood cells (RBCs) has been studied as a typical example of cryobiology methodology. To date, a mature and long-term cryopreservation process for RBCs has been developed, which has the weakness of complicated procedures due to high concentrations of glycerol (Gly). Therefore, it is still a research focus to find a new method for cryopreservation of RBCs to reduce the concentrations of cryoprotectants (CPAs). In this study, alginate hydrogels, which have been widely used in preservation research, were selected because of their advantages such as lower cost, cytocompatibility, and crosslinking occurring under mild conditions. With a variety of CPA solutions, the RBC recovery with the cryopreservation of RBCs and RBC-laden hydrogel microfibers was compared in different situations. It was found that hydrogel microfiber encapsulation enhances cryopreservation of human RBCs with low concentrations of CPAs. And Gly can be removed by washing directly with a 0.9% sodium chloride solution. This study validated the feasibility of cryopreservation of RBC-laden hydrogel microfibers. It may provide a new and evolving direction for reducing the concentrations of CPAs used in the preservation of RBCs.
Keywords: cryopreservation by rapid freezing; cryoprotectants; hydrogel microfibers; red blood cells.