Department of Chemistry, Gachon University, Seongnam-daero 1342, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
Department of Chemistry, Gachon University, Seongnam-daero 1342, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
Colloids Surf B Biointerfaces. 2021 Apr;200:111587. doi: 10.1016/j.colsurfb.2021.111587. Epub 2021 Jan 22.
Here, we demonstrate a capillary-sensing platform based on liquid crystals (LCs) confined in microcapillaries for simple and sensitive detection of acetylcholinesterase (AChE) and its inhibitors. LC droplets were formed through sequential injection of LCs and an aqueous solution into trichloro(octyl)silane (OTS)-treated microcapillaries. When the confined LC droplets make contact with a cationic surfactant solution, myristoylcholine chloride (Myr), the formation of a Myr monolayer at the aqueous/LC interface induces a horizontal orientation of the LCs at the interface along the microcapillary, producing an optical LC droplet texture of a four-petal shape. On the other hand, AChE can catalyze the hydrolysis of Myr into choline and myristic acid. The hydrolyzed Myr is unable to form a monolayer at the aqueous/LC interface, and therefore the confined LC droplets exhibit two bright-lined optical images when in contact with the pre-incubated mixture of Myr and AChE, corresponding to the homeotropic orientation of LCs at the interface. However, in the presence of AChE-inhibiting pesticides, such as fenobucarb and malathion, the activity of AChE is inhibited, and thus, the enzymatic hydrolysis of Myr cannot occur. As a result, the confined LC droplets present the four petal-shaped optical images when in contact with the pre-incubated mixture of Myr, AChE, and pesticides. Based on this principle, an LC-based microcapillary sensor was developed and utilized for the detection of pesticides. Using this sensing platform, fenobucarb and malathion were detected at limits of 5 pg/mL and 2.5 pg/mL, respectively. Moreover, the proposed biosensor was successfully applied to the determination of pesticides in real river water. Therefore, this LC-based microcapillary sensor is a promising platform for simple, rapid, and label-free detection of pesticides with very high sensitivity.
在这里，我们展示了一种基于液晶（LC）的毛细管传感平台，用于简单灵敏地检测乙酰胆碱酯酶（AChE）及其抑制剂。LC 液滴通过将 LC 和水溶液顺序注入三氯（辛基）硅烷（OTS）处理的微毛细管中形成。当被限制的 LC 液滴与阳离子表面活性剂溶液十四酰胆碱氯（Myr）接触时，在水/LC 界面形成的 Myr 单层诱导 LC 在界面处沿微毛细管水平取向，产生具有四瓣形状的光学 LC 液滴纹理。另一方面，AChE 可以催化 Myr 的水解生成胆碱和肉豆蔻酸。水解的 Myr 无法在水/LC 界面形成单层，因此当与预先孵育的 Myr 和 AChE 混合物接触时，被限制的 LC 液滴呈现出两个明亮线的光学图像，对应于界面处 LC 的各向异性取向。然而，在存在 AChE 抑制剂农药（如苯氧威和马拉硫磷）的情况下，AChE 的活性受到抑制，因此 Myr 的酶促水解不能发生。因此，当与预先孵育的 Myr、AChE 和农药混合物接触时，被限制的 LC 液滴呈现出四瓣形的光学图像。基于这一原理，我们开发了一种基于 LC 的微毛细管传感器，并将其用于检测农药。使用这个传感平台，苯氧威和马拉硫磷的检测限分别为 5 pg/mL 和 2.5 pg/mL。此外，该传感器已成功应用于实际河水样品中农药的测定。因此，这种基于 LC 的微毛细管传感器是一种很有前途的平台，用于简单、快速、无标记地检测农药，具有很高的灵敏度。
