Xu H F, Hao B T, Liu L J, Tang L L, Liu B L
Institute of Biothermal Science, Shanghai University for Science and Technology, Shanghai, China.
Cryo Letters. 2016 Nov/Dec;37(6):406-410.
BACKGROUND: Vitrification, the ice-free cryopreservation, develops rapidly and can become an ideal method for long-term preservation of cells and tissues. But up to now it is not practical for samples with large size because of the ultra-rapid cooling rate required. It has been reported that nanoparticles improve heat conductivity of solutions.
In this study, Hydroxyapatite (HA) nanoparticles（20, 40 or 60nm）at 0.1 %, 0.5 % or 1 % (w/w) were added into glycerol solutions. Glass transition temperature and devitrification temperature of aqueous glycerol solutions with/without HA nanoparticles were measured by a differential scanning calorimeter(DSC) at a cooling rate of 150 degree C/min and a warming rate of 10 degree C/ min.
Glass-transition temperatures and devitrification temperatures of glycerol aqueous solutions increased after the incorporation of HA nanoparticles. In the study using slow cooling rate of 10 degree C/min and warming rate of 5 degree C/min, the fraction of unfrozen water in the 50 % (w/w) glycerol solution increases steadily with the addition of HA nanoparticles. The findings have significant implications for biomaterial cryopreservation.
背景：玻璃化冷冻法，即无冰冷冻保存技术，发展迅速，有望成为细胞和组织长期保存的理想方法。但由于所需的超快速冷却速率，目前对于大尺寸样本并不实用。据报道，纳米颗粒可提高溶液的热导率。
在本研究中，将0.1%、0.5%或1%（w/w）的20、40或60纳米的羟基磷灰石（HA）纳米颗粒添加到甘油溶液中。使用差示扫描量热仪（DSC）以150℃/分钟的冷却速率和10℃/分钟的升温速率测量含/不含HA纳米颗粒的甘油水溶液的玻璃化转变温度和脱玻璃化温度。
加入HA纳米颗粒后，甘油水溶液的玻璃化转变温度和脱玻璃化温度升高。在以10℃/分钟的缓慢冷却速率和5℃/分钟的升温速率进行的研究中，随着HA纳米颗粒的添加，50%（w/w）甘油溶液中未冻水的比例稳步增加。这些发现对生物材料冷冻保存具有重要意义。
