Imaging Trypsin Activity through Changes in the Orientation of Liquid Crystals Coupled to the Interactions between a Polyelectrolyte and a Phospholipid Layer
Imaging Trypsin Activity through Changes in the Orientation of Liquid Crystals Coupled to the Interactions between a Polyelectrolyte and a Phospholipid Layer
复制标题
DOI：
10.1021/am300043d
复制
发表时间：
2012-03-01
影响因子：
9.5
通讯作者：
Jang, Chang-Hyun
中科院分区：
文献类型：
--
作者：
Hu, Qiong-Zheng;Jang, Chang-Hyun
在这项研究中，我们开发了一种新型的液晶（LC）为基础的传感器的实时和无标记的酶活性的监测，通过改变方向的LC耦合到之间的相互作用的磷脂和磷脂。将聚-L-赖氨酸（PLL）的水溶液转移到磷脂二油酰-sn-甘油基-3-磷酸-rac-（1-甘油）钠盐（DOPG）在水/LC界面处的自组装单层上后，LC从暗变为亮。带正电荷的PLL和带负电荷的DOPG之间的相互作用驱动磷脂膜的重组，这诱导了LC从垂面到平面状态的取向转变。由于丝氨酸内肽酶胰蛋白酶可以酶促催化PLL的水解，在将PLL和胰蛋白酶的混合溶液转移到DOPG修饰的LC界面上后，没有观察到光学响应的暗到亮的偏移，表明LC中没有发生取向转变。然而，当用PLL的水溶液代替光池中的混合物时，观察到从暗到亮的光学响应。用胰蛋白酶或PLL和失活胰蛋白酶的水性混合物进行的对照实验进一步证实了这种方法的可行性。胰蛋白酶的检测限被确定为类似于1 μ g/mL。这种方法具有很大的希望，用于开发基于LC的传感器，用于检测酶促反应的情况下，酶的生物降解底物可能会破坏膜的组织，并诱导LC在水/LC界面的取向转变。
In this study, we developed a new type of liquid crystal (LC)-based sensor for the real-time and label-free monitoring of enzymatic activity through changes in the orientation of LCs coupled to the interactions between polyelectrolyte and phospholipid. The LCs changed from dark to bright after an aqueous solution of poly-L-lysine (PLL) was transferred onto a self-assembled monolayer of the phospholipid, dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG), at the aqueous/LC interface. Interactions between the positively charged PLL and the negatively charged DOPG drove the reorganization of the phospholipid membrane, which induced an orientational transition in the LCs from a homeotropic to planar state. Since the serine endopeptidase trypsin can enzymatically catalyze the hydrolysis of PLL, the dark-to-bright shift in the optical response was not observed after transferring a mixed solution of PLL and trypsin onto the DOPG-decorated LC interface, indicating that no orientational transitions in the LCs occurred. However, the optical response from dark to bright was observed when the mixture in the optical cell was replaced by an aqueous solution of PLL. Control experiments with trypsin or an aqueous mixture of PLL and deactivated trypsin further confirmed the feasibility of this approach. The detection limit of trypsin was determined to be similar to 1 mu g/mL. This approach holds great promise for use in the development of LC-based sensors for the detection of enzymatic reactions in cases where the biological polyelectrolyte substrates of enzymes could disrupt the organization of the membrane and induce orientational transitions of LCs at the aqueous/LC interface.