Cryopreservation, which refers to preservation of cells or tissues at subzero temperatures, inevitably involves the problem of cryoinjury caused by ice crystals. The application of an external electric field during the freezing process has been shown to be a promising approach to produce miniature ice grains and decrease the fraction of ice crystallization at a slow cooling rate. Thus, the dielectric and thermodynamic properties of NaCl-H₂O binary solutions at subzero temperatures were tremendously important for understanding the mechanism of ice formation under the manipulation of an AC electric field in biopreservation. However, there was still a lack of relevant information in the literature. The first objective of this study was to systematically measure the dielectric spectrum of 0.9% NaCl-H₂O binary solutions at temperatures ranging from −100°C to 0°C with a cooling/heating rate of 2°C/min. We further measured the thermodynamic properties of a 0.9% NaCl-H₂O binary solution while applying a series of electric fields near its dielectric relaxation frequency. The effect of the electric field on the crystal morphology was studied last. Pure water was selected as the control group. The results showed that an AC electric field can alter the thermodynamic process and thus the phase transition and ice crystal structure could be manipulated. It was concluded that the AC electric-assistant preservation method will be a promising technology in cryopreservation.

中文翻译：

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交流电场控制下NaCl-H2O二元溶液的相变行为

冷冻保存是指在零度以下的温度下保存细胞或组织，不可避免地涉及冰晶引起的冷冻损伤问题。在冷冻过程中施加外部电场已被证明是一种有前途的方法，可以产生微型冰粒并以缓慢的冷却速度降低冰结晶的比例。因此，NaCl-H ₂ O 二元溶液在零下温度下的介电和热力学性质对于理解在生物保存中交流电场控制下的冰形成机制非常重要。然而，文献中仍然缺乏相关信息。本研究的第一个目标是系统地测量 0.9% NaCl-H ₂的介电光谱O 二元溶液，温度范围为 -100°C 至 0°C，冷却/加热速率为 2°C/分钟。我们进一步测量了 0.9% NaCl-H ₂ O 二元溶液的热力学性质，同时在其介电弛豫频率附近施加了一系列电场。最后研究了电场对晶体形貌的影响。选择纯水作为对照组。结果表明，交流电场可以改变热力学过程，从而可以操纵相变和冰晶结构。得出结论，交流电辅助保存方法将是一种很有前途的冷冻保存技术。