Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, WI 53706-1607, USA.
Science. 2011 Jun 10;332(6035):1297-300. doi: 10.1126/science.1195639. Epub 2011 May 19.
The ordering of liquid crystals (LCs) is known to be influenced by surfaces and contaminants. Here, we report that picogram per milliliter concentrations of endotoxin in water trigger ordering transitions in micrometer-size LC droplets. The ordering transitions, which occur at surface concentrations of endotoxin that are less than 10(-5) Langmuir, are not due to adsorbate-induced changes in the interfacial energy of the LC. The sensitivity of the LC to endotoxin was measured to change by six orders of magnitude with the geometry of the LC (droplet versus slab), supporting the hypothesis that interactions of endotoxin with topological defects in the LC mediate the response of the droplets. The LC ordering transitions depend strongly on glycophospholipid structure and provide new designs for responsive soft matter.
众所周知，液体晶体（LCs）的排列受到表面和污染物的影响。在这里，我们报告说，水中每毫升微克级的内毒素浓度会引发微米大小的 LC 液滴的有序转变。这些有序转变发生在内毒素表面浓度小于 10^-5 朗缪尔（Langmuir）的情况下，不是由于吸附物引起的 LC 界面能变化所致。LC 对内毒素的敏感性随着 LC 的几何形状（液滴与平板）变化而变化了六个数量级，这支持了内毒素与 LC 中的拓扑缺陷相互作用介导液滴响应的假设。LC 的有序转变强烈依赖于糖脂的结构，并为响应性软物质提供了新的设计。
