Department of Mechanical Engineering and Engineering Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
Sci Rep. 2016 Jul 8;6:28795. doi: 10.1038/srep28795.
Dry preservation of biologics in sugar glasses is regarded as a promising alternative to conventional cryopreservation. Evidence from various studies has suggested that there is a critical range of water content beyond which the viability of preserved biologics can be greatly compromised. In this study the viability of T-cells was determined as a function of end water content after microwave-assisted drying in trehalose solutions. Hydrogen-bonding and clustering phenomena in trehalose solutions of the same moisture content were also evaluated using molecular dynamics simulation. Post-rehydration viability decreased dramatically within the range of 0.1-1 gH2O/gdw. Molecular modeling revealed that as the water content approached 0.1 gH2O/gdw the matrix formed a large interconnected trehalose skeleton with a minimal number of bound water molecules scattered in the bulk. The diffusion coefficients of trehalose oxygen atoms most distant from the glycosidic linkage fluctuated around 7.5 × 10(-14) m(2)/s within the range of 0.02-0.1 gH2O/gdw and increased again to ~1.13 × 10(-13) m(2)/s at 0.01 gH2O/gdw and below due to the loss of water in the free volume between trehalose molecules. These insights can guide the optimal selection of final moisture contents to advance dry preservation methods.
糖玻璃中的生物制品干燥保存被认为是传统冷冻保存的一种有前途的替代方法。来自各种研究的证据表明，存在一个关键的含水量范围，超过这个范围，保存的生物制品的存活能力可能会大大降低。在这项研究中，通过微波辅助干燥在海藻糖溶液中确定了 T 细胞的存活能力作为终含水量的函数。还使用分子动力学模拟评估了相同含水量的海藻糖溶液中的氢键和团聚现象。再水合后的存活率在 0.1-1 gH2O/gdw 的范围内急剧下降。分子建模表明，随着含水量接近 0.1 gH2O/gdw，基质形成了一个大的相互连接的海藻糖骨架，只有少数结合水分子散布在基质中。与糖苷键最远的海藻糖氧原子的扩散系数在 0.02-0.1 gH2O/gdw 的范围内围绕 7.5×10(-14) m(2)/s 波动，并在 0.01 gH2O/gdw 及以下再次增加到约 1.13×10(-13) m(2)/s，这是由于海藻糖分子之间的自由体积中失去了水分。这些见解可以指导最终水分含量的最佳选择，以推进干燥保存方法。
