Čechová Katarína, Maťko Igor, Rusnák Jaroslav, Švajdlenková Helena, Klbik Ivan, Lakota Ján, Šauša Ondrej
Institute of Physics SAS Dúbravská cesta 9 845 11 Bratislava Slovak Republic
Polymer Institute SAS Dúbravská cesta 9 845 41 Bratislava Slovak Republic.
RSC Adv. 2019 Oct 24;9(59):34299-34310. doi: 10.1039/c9ra06305f. eCollection 2019 Oct 23.
This work investigates the free-volume properties of the dimethyl sulfoxide (DMSO)-water mixtures by positron annihilation lifetime spectroscopy over a wide temperature range of 20-320 K. The processes of melting and solidification of the water, DMSO and the DMSO-water mixtures at 1.8, 2.0 and 10% vol. DMSO respectively were studied. It was found that the recrystallization during heating of the water-DMSO cryoprotective mixtures above 160 K at low DMSO concentrations is affected by the amount of DMSO in the mixture. The amount of amorphous phase formed during cooling influences the hysteresis between cooling and heating cycles which could be crucial for cell survival. Experiments also show the time dependence of crystallization which indicates that rapid heating can suppress this secondary crystallization which is undesirable during the cell thawing process. Similar concentrations of DMSO (1.8% and 2% vol. DMSO in water) where a 2% vol. DMSO mixture secures cell survival but 1.8 vol% does not, showed differences in structural and dynamic properties that are key factors in cell survival. These results were supported by differential scanning calorimetry and low frequency dielectric spectroscopy measurements. The obtained data are in strong agreement with the observed cryoprotective efficacy of the DMSO-water mixtures on living cells.
本研究通过正电子湮没寿命谱在20 - 320 K的宽温度范围内研究了二甲基亚砜（DMSO）-水混合物的自由体积性质。分别研究了水、DMSO以及体积分数为1.8%、2.0%和10%的DMSO -水混合物的熔化和凝固过程。研究发现，在低DMSO浓度下，水 - DMSO冷冻保护混合物在160 K以上加热时的重结晶受混合物中DMSO含量的影响。冷却过程中形成的非晶相数量会影响冷却和加热循环之间的滞后现象，这对细胞存活可能至关重要。实验还表明了结晶的时间依赖性，这表明快速加热可以抑制这种在细胞解冻过程中不希望出现的二次结晶。类似浓度的DMSO（水中体积分数为1.8%和2%的DMSO），其中体积分数为2%的DMSO混合物能确保细胞存活，而1.8体积%的则不能，它们在结构和动力学性质上存在差异，这些是细胞存活的关键因素。这些结果得到了差示扫描量热法和低频介电谱测量的支持。所获得的数据与观察到的DMSO -水混合物对活细胞的冷冻保护效果高度一致。
