ETH Zurich, Department of Health Sciences and Technology, Schmelzbergstrasse 9, LFO E23 Zurich 8092, Switzerland.
"Sapienza" Universita' di Roma, Dipartimento di Fisica, P.le A. Moro 2, 00185 Roma, Italy.
Soft Matter. 2021 Mar 4;17(8):2158-2169. doi: 10.1039/d0sm01886d.
Biological liquid crystals, originating from the self-assembly of biological filamentous colloids, such as cellulose and amyloid fibrils, show a complex lyotropic behaviour that is extremely difficult to predict and characterize. Here we analyse the liquid crystalline phases of amyloid fibrils, and sulfated and carboxylated cellulose nanocrystals and measure their Frank-Oseen elastic constants K1, K2 and K3 by four different approaches. The first two approaches are based on the benchmark of the predictions of: (i) a scaling form and (ii) a variational form of the Frank-Oseen energy functional with the experimental critical volumes at order-order liquid crystalline transitions of the tactoids. The third and the fourth methods imply: (iii) the direct scaling equations of elastic constants and (iv) a molecular theory predicting the elastic constants from the experimentally accessible contour length distributions of the filamentous colloids. These three biological systems exhibit diverse liquid crystalline behaviour, governed by the distinct elastic constants characterizing each colloid. Differences and similarities among the three systems are highlighted and interpreted based on the present analysis, providing a general framework to study dispersed liquid crystalline systems.
生物液晶源于生物丝状胶体的自组装，如纤维素和淀粉样纤维，表现出复杂的溶致行为，极难预测和表征。在这里，我们分析了淀粉样纤维、硫酸化和羧化纤维素纳米晶的液晶相，并通过四种不同的方法测量了它们的弗兰克-奥森弹性常数 K1、K2 和 K3。前两种方法基于以下基准：（i）弗兰克-奥森能量泛函的标度形式和（ii）变分形式的预测，实验临界体积在拟晶有序-有序液晶转变处。第三和第四种方法意味着：（iii）弹性常数的直接标度方程和（iv）从实验可获得的丝状胶体的轮廓长度分布预测弹性常数的分子理论。这三个生物系统表现出不同的液晶行为，由每个胶体的特征弹性常数决定。基于目前的分析，突出并解释了这三个系统之间的差异和相似之处，为研究分散液晶系统提供了一个通用框架。
