Human umbilical vein endothelial cells (HUVECs) have wide applications in tissue engineering, drug delivery, and other fields due to their low antigenicity. Therefore, it is of great significance to effectively cryopreserve HUVECs for subsequent use (i.e., transport, long-term storage of cell banks). However, many commonly used cryoprotective agents (CPAs) are cytotoxic, so finding ideal CPAs to reduce the damage will pave the way for the application of HUVEC's cryopreservation. In this study, sodium alginate (SA) was employed as one of the main CPAs in a closed polytetrafluoroethylene (PTFE) loop used for cryopreservation with fast freezing of HUVECs. The ice crystal growth process was observed and the thermal enthalpy changes and osmolality of different solutions were tested. Moreover, the effects on cell viability and recovery were examined. The results showed that the addition of SA delayed the growth of ice crystals and decreased the number of ice crystals. Specifically, when 0.5% (w/v) SA was added to the CPAs, the cell survival increased by 10%. It is proved in this study that SA can be used as a novel CPA in combination with PTFE for the fast freezing of HUVECs, which is expected to improve the survival rate of cells and promote the exploration of protectants and cryopreservation in the future.

中文翻译：

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海藻酸钠作为一种新型的低温保护剂，用于在封闭的聚四氟乙烯环中冷冻保存内皮细胞。

人脐静脉内皮细胞（HUVEC）由于其低抗原性而在组织工程，药物输送和其他领域具有广泛的应用。因此，有效地冷冻保存HUVEC供随后使用（即运输，长期储存细胞库）具有重要意义。但是，许多常用的冷冻保护剂（CPA）具有细胞毒性，因此寻找理想的CPA来减少损伤将为HUVEC冷冻保存的应用铺平道路。在这项研究中，海藻酸钠（SA）被用作闭式聚四氟乙烯（PTFE）回路中的主要CPA之一，用于冷冻保存HUVEC并快速冷冻。观察到冰晶的生长过程，并测试了不同溶液的热焓变化和渗透压。此外，检查了对细胞活力和恢复的影响。结果表明，SA的加入延迟了冰晶的生长并减少了冰晶的数量。具体而言，当将0.5％（w / v）的SA添加到CPA中时，细胞存活率提高了10％。这项研究证明，SA可以与PTFE结合用作新型CPA，用于HUVEC的快速冷冻，有望提高细胞的存活率，并在将来促进保护剂的探索和冷冻保存。