PHYSICAL PROBLEMS WITH THE VITRIFICATION OF LARGE BIOLOGICAL-SYSTEMS
PHYSICAL PROBLEMS WITH THE VITRIFICATION OF LARGE BIOLOGICAL-SYSTEMS
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DOI：
10.1016/0011-2240(90)90038-6
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发表时间：
1990-10-01
期刊：
影响因子：
2.7
通讯作者：
WILLIAMS, RJ
中科院分区：
文献类型：
--
作者：
FAHY, GM;SAUR, J;WILLIAMS, RJ
玻璃化是成功冷冻保存成熟哺乳动物器官的一条诱人的潜在途径，但到目前为止，关于玻璃化的现代低温生物学研究主要致力于用溶液和直径从约6到约100微米的生物系统进行实验。本文件侧重于与大型生物系统特别相关的问题，即那些大小从大约10毫升到大约1.5升的系统。提供了新的定性数据，说明了样品大小对成核概率和最终冰晶尺寸的影响，以及在玻璃化转变温度(Tg)或更低时破裂的可能性。成核、晶体生长和断裂取决于样品中的冷却速度和温度梯度的大小，而温度梯度的大小又取决于样品的尺寸、几何形状和冷却技术(环境热历史和热均匀度)。提供了关于温度梯度、冷却速度和断裂温度的定量数据，作为样本大小的函数。主要结论如下。首先，冷却速度(从0.2℃/min左右到2.5℃/min左右)对47-50%(w/w)丙二醇水溶液中的成核和晶体生长的温度相关过程有深远的影响。其次，破裂强烈地依赖于冷却速度和热均匀性，如果冷却缓慢且均匀，对于482毫升的样品，破裂可以推迟到Tg以下约25摄氏度。第三，载体溶液的存在降低了玻璃化(CV)所需的冷冻保护剂的浓度。然而，无论是否存在载体溶液，大于约10ml的样品的CV都显著高于较小的样品的CV。
Vitrification is an attractive potential pathway to the successful cryopreservation of mature mammalian organs, but modern cryobiological research on vitrification to date has been devoted mostly to experiments with solutions and with biological systems ranging in diameter from about 6 through about 100 .mu.m. The present paper focuses on concerns which are particularly relevant to large biological systems, i.e., those systems ranging in size from approximately 10 ml to approximately 1.5 liters. New qualitative data are provided on the effect of sample size on the probability of nucleation and the ultimate size of the resulting ice crystals as well as on the probability of fracture at or below Tg. Nucleation, crystal growth, and fracture depend on cooling velocity and the magnitude of thermal gradients in the sample, which in turn depend on sample size, geometry, and cooling technique (environmental thermal history and thermal uniformity). Quantitative data on thermal gradients, cooling rates, and fracture temperatures are provided as a function of sample size. The main conclusions are as follows. First, cooling rate (from about 0.2 to about 2.5.degree.C/min) has a profound influence on the temperature-dependent processes of nucleation and crystal growth in 47-50% (w/w) solutions of propylene glycol. Second, fracturing depends strongly on cooling rate and thermal uniformity and can be postponed to about 25.degree.C below Tg for a 482-ml sample if cooling is slow and uniform. Third, the presence of a carrier solution reduces the concentration of cryoprotectant needed for vitrification (Cv). However, the Cv of samples larger than about 10 ml is significantly higher than the Cv of smaller samples whether a carrier solution is present or not.