Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
Interdisciplinary Research Center for Advanced Materials (IRC-AM), King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
Molecules. 2022 Feb 21;27(4):1453. doi: 10.3390/molecules27041453.
This focused review presents various approaches or formats in which liquid crystals (LCs) have been used as stimuli-responsive sensors. In these sensors, the LC molecules adopt some well-defined arrangement based on the sensor composition and the chemistry of the system. The sensor usually consists of a molecule or functionality in the system that engages in some form of specific interaction with the analyte of interest. The presence of analyte brings about the specific interaction, which then triggers an orientational transition of the LC molecules, which is optically discernible via a polarized optical image that shows up as dark or bright, depending on the orientation of the LC molecules in the system (usually a homeotropic or planar arrangement). The various applications of LCs as biosensors for glucose, protein and peptide detection, biomarkers, drug molecules and metabolites are extensively reviewed. The review also presents applications of LC-based sensors in the detection of heavy metals, anionic species, gases, volatile organic compounds (VOCs), toxic substances and in pH monitoring. Additionally discussed are the various ways in which LCs have been used in the field of material science. Specific attention has been given to the sensing mechanism of each sensor and it is important to note that in all cases, LC-based sensing involves some form of orientational transition of the LC molecules in the presence of a given analyte. Finally, the review concludes by giving future perspectives on LC-based sensors.
本文重点综述了将液晶（LC）用作响应性传感器的各种方法或形式。在这些传感器中，液晶分子根据传感器组成和系统化学采用某种明确定义的排列。传感器通常由系统中的分子或官能团组成，该分子或官能团与感兴趣的分析物发生某种形式的特定相互作用。分析物的存在引发特定相互作用，继而触发液晶分子的取向转变，这可以通过偏振光图像光学上识别，其显示为暗或亮，具体取决于系统中液晶分子的取向（通常为各向异性或平面排列）。本文广泛综述了 LC 作为葡萄糖、蛋白质和肽检测、生物标志物、药物分子和代谢物的生物传感器的各种应用。该综述还介绍了基于 LC 的传感器在重金属、阴离子物种、气体、挥发性有机化合物（VOC）、有毒物质和 pH 监测中的检测应用。此外，还讨论了 LC 在材料科学领域的各种应用。特别关注每个传感器的传感机制，需要注意的是，在所有情况下，基于 LC 的传感都涉及在给定分析物存在下液晶分子的某种形式的取向转变。最后，本文通过对基于 LC 的传感器的未来展望结束。
