Dual Dependence Of The Viscosity Of Ternary Solution On The Temperature And The Concentration

In biopreservation, the viscosities of commonly used ternary cryoprotectant solutions at subzero temperatures is of significant importance to the understanding of the intracellular ice formation (IIF) and molecular transport process. However, he viscosity data of the ternary solutions is scarce in literature. In addition, to the best of our knowledge, the effect of nanoparticles on the viscosities of these solutionss rarely reported. Therefore, this study conducted the following research which was focused on the viscosities of the ternary cryoprotectant solutions:1) Systematically measured the subzero viscosities of dimethylsulfoxide (Me2SO)-H2O-NaCl and glycerol-H2O-NaCl ternary solutions;2) Study the dual dependence of these ternary solutions’viscosity on the temperature and the concentration.3) Built the models to correctly predict the viscosities of the ternary protectant solutions at subzero temperatures;4) Explored the effect of hydroxyapatite (HA) nanoparticles on the viscosity.5) Designed a new viscometer system to to improve the deficiency existed in rotary viscosimeter system;The experiment in this study was divided into two parts. Firstly, we measured the viscosity at multiple CPA concentrations [0.3-0.75(w/w)] in saline solution with and without nanoparticles at subzero temperatures (0to-30℃). The data exhibited a good fit to the Williams-Landel-Ferry (WLF) equation. We then measured the viscosity of the residual unfrozen ternary solutions with and without nanoparticles during equilibrium freezing.Based on the analysis of the obtained viscosity data, we concluded that:1) With the same concentration, the viscosities of CPA solutions were increasing with the decreasing of the temperature. However, at a certain temperature, for Me2SO-H2O-NaCl solutions, a maximum occurred in the isotherms within the range of Me2SO mass fractions that were tested, while the viscosity of glycerol-H2O-NaCl solutions continually rises as the glycerol concentration is increased. The free volume theory was introduced as the explanation.2) HA nanoparticles made the solution more viscous, suggesting applications for these nanoparticles in preventing cell dehydration, ice nucleation, and ice growth during freezing and thawing in cryopreservation.