Inhibition of nucleation and growth of ice by poly(vinyl alcohol) in vitrification solution
Inhibition of nucleation and growth of ice by poly(vinyl alcohol) in vitrification solution
复制标题
DOI：
10.1016/j.cryobiol.2009.04.013
复制
发表时间：
2009-08-01
期刊：
影响因子：
2.7
通讯作者：
Lu, Shu-Shen
中科院分区：
文献类型：
--
作者：
Wang, Hai-Yan;Inada, Takaaki;Lu, Shu-Shen
控制冰的形成是生物物质低温保存的关键。先前已经报道了使用抑制玻璃化溶液中的冰成核的几种添加剂的成功玻璃化。在这些添加剂中，我们重点研究了合成聚合物聚乙烯醇（PVA），并使用配备低温显微镜的差示扫描量热法（DSC）系统研究了PVA对35%（w/w）1，2-丙二醇水溶液中冰的成核和生长的影响。首先，使用DSC系统测量溶液的冻结温度，然后基于使用低温显微镜获得的图像，在0%和3%（w/w）之间的不同PVA浓度下，评估冷却期间溶液中冰分数的变化。基于冰分数，还评估了冷却期间残余溶液浓度的变化，然后绘制在1，2-丙二醇水溶液的状态图上。结果表明，当部分玻璃化和部分冻结状态是故意允许的，添加PVA有效地抑制不仅冰成核，但也冰生长的玻璃化溶液。PVA对玻璃化溶液中冰生长的影响主要是由于质量传输的动力学限制的基础上解释。只有当冰的生长速率降低到临界值以下时，界面动力学也可能限制玻璃化溶液中冰的生长。这与当冰生长速率低于临界值时PVA以与抗冻蛋白相同的方式表现出独特的抗冻活性的事实相一致。(C)2009 Elsevier Inc. All rights reserved.
Control of ice formation is crucial in cryopreservation of biological substances. Successful vitrification using several additives that inhibit ice nucleation in vitrification solutions has previously been reported. Among these additives, here we focused on a synthetic polymer, poly(vinyl alcohol) (PVA), and investigated the effects of PVA on nucleation and growth of ice in 35% (w/w) aqueous 1,2-propanediol solution by using a differential scanning calorimetry (DSC) system equipped with a cryomicroscope. First, the freezing temperature of the solution was measured using the DSC system, and then the change in ice fraction in the solution during cooling was evaluated based on images obtained using the cryomicroscope, at different concentrations of PVA between 0% and 3% (w/w). Based on the ice fraction, the change in residual solution concentration during cooling was also evaluated and then plotted on the state diagram of aqueous 1,2-propanediol solution. Results indicated that, when the partially glassy and partially frozen state was intentionally allowed, the addition of PVA effectively inhibited not only ice nucleation but also ice growth in the vitrification solution. The effect of PVA on ice growth in the vitrification solution was explained based on kinetic limitations mainly due to mass transport. The interfacial kinetics also might limit ice growth in the vitrification solution only when the ice growth rate decreased below a critical value. This coincides with the fact that PVA exhibits a unique antifreeze activity in the same manner as antifreeze proteins when ice growth rate is lower than a critical value. (C) 2009 Elsevier Inc. All rights reserved.