The liquid crystalline state of matter arises from orientation-dependent, non-covalent interactions between molecules within condensed phases. Because the balance of intermolecular forces that underlies the formation of liquid crystals (LCs) is delicate, this state of matter can, in general, be easily perturbed by external stimuli (such as an electric field in a display). In this review, we present an overview of recent efforts that have focused on exploiting the responsiveness of LCs as the basis of chemical and biological sensors. In this application of LCs, the challenge is to design liquid crystalline systems that undergo changes in organization when perturbed by targeted chemical and biological species of interest. The approaches described below revolve around the design of interfaces that selectively bind targeted species, thus leading to surface-driven changes in the organization of the LCs. Because LCs possess anisotropic optical and dielectric properties, a range of different methods can be used to read out the changes in organization of LCs that are caused by targeted chemical and biological species. This review focuses on principles for LC-based sensors that provide an optical output.

物质的液晶态是由凝聚相内分子之间依赖取向的非共价相互作用产生的。由于液晶 (LC) 形成过程中分子间力的平衡非常微妙，因此这种物质状态通常很容易受到外部刺激（例如显示器中的电场）的干扰。在这篇综述中，我们概述了最近的努力，这些努力的重点是利用液晶的响应能力作为化学和生物传感器的基础。在液晶的这种应用中，面临的挑战是设计液晶系统，当受到目标化学和生物物种的干扰时，该系统会发生组织变化。下面描述的方法围绕选择性结合目标物质的界面设计，从而导致液晶组织的表面驱动变化。由于液晶具有各向异性的光学和介电特性，因此可以使用一系列不同的方法来读出由目标化学和生物物种引起的液晶组织的变化。本综述重点介绍提供光学输出的基于 LC 的传感器的原理。