School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China.
Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA.
J Colloid Interface Sci. 2021 Jan 15;582(Pt B):610-618. doi: 10.1016/j.jcis.2020.08.068. Epub 2020 Aug 25.
Ethanol was used to induce coacervation in aqueous solutions of gelatin. Coacervation resulted from phase separation driven by ethanol as a poor solvent for gelatin, impacting aggregation of gelatin chains. Static coacervation was performed to investigate coacervate morphology, and gelatin concentration and ethanol temperature influenced the morphologies of the gelatin coacervates. High-concentration gelatin solutions (>4.8 wt%) treated with lower temperature ethanol (<25 °C) formed network morphologies, while low-concentration gelatin solution (<4.8 wt%) treated with ethanol near room temperature formed nanosphere assemblies. Dispersive nanospheres were obtained after treatment with higher temperature ethanol (~45 °C). Stirring the mixture of gelatin solution and ethanol resulted in dispersed nanospheres where the size was adjusted by changing the volume ratio of aqueous gelatin solution and ethanol (V:V) and the gelatin concentration. Turbidity and absorbance measurements were carried out to further investigate coacervation dynamics. The cocervation system reached dynamic equilibrium according to the V:V, suggesting phase separation and molecular arrangements were key. DLS results showed that reversible changes in coacervate radius could be attained by periodic heating and cooling cycles (25-60 °C). This work provides useful information for constructing gelatin-based materials using a facile coacervation method.
乙醇被用于诱导明胶水溶液中的凝聚。凝聚是由乙醇作为明胶的不良溶剂引起的相分离驱动的，这影响了明胶链的聚集。进行了静态凝聚以研究凝聚物的形态，明胶浓度和乙醇温度影响明胶凝聚物的形态。用较低温度的乙醇（<25°C）处理高浓度明胶溶液（>4.8 wt％）形成网络形态，而用接近室温的乙醇处理低浓度明胶溶液（<4.8 wt％）形成纳米球组装体。用较高温度的乙醇（约 45°C）处理后，得到分散的纳米球。通过改变水相明胶溶液和乙醇的体积比（V:V）和明胶浓度来搅拌明胶溶液和乙醇的混合物，可以调节所得分散纳米球的尺寸。浊度和吸光度测量进一步研究了凝聚动力学。根据 V:V，凝聚系统达到了动力学平衡，这表明相分离和分子排列是关键。DLS 结果表明，通过周期性的加热和冷却循环（25-60°C）可以实现凝聚物半径的可逆变化。这项工作为使用简便的凝聚方法构建基于明胶的材料提供了有用的信息。
