Background: Cryopreservation of hematopoietic stem cells (HSCs) has widely been used in stem cell transplantation and cellular therapy treating various human diseases. However, the current conventional cooling approach for the cryopreservation of HSCs has the following potential problems: (1) requirement of a very expensive computer-programmed liquid nitrogen freezer (LNF) for the cooling rate control, (2) a large consumption of liquid nitrogen, (3) periodic breakdown of the LNF due to the mechanical failure of the liquid nitrogen valves (i.e., magnetic-solenoid valves) inside the LNF, and (4) constant monitoring of the LNF operation during the HSCs cooling process.
Objective: To test and evaluate a simple and reliable approach for the cryopreservation of HSCs using the passive cooling technique.
Materials and methods: A passive cooling-rate-controlled device (PCD) was developed and used to cryopreserve HSCs. The PCD is inexpensive, simple, and user-friendly, which needs only the minimum maintenance and no consumption of liquid nitrogen. The PCD was compared to the LNF for the cryopreservation of HSCs in the present study through experiments. The cell viability and functionality were evaluated after cryopreservation.
Results: In comparison with the LNF method, the PCD approach enabled high cell viability/survival, recovery rate, and functionality after cryopreservation processes.
Conclusion: The PCD offers a cost-effective, simple, and reliable approach for the optimal cryopreservation of HSCs.