Sensing Small Molecule Interactions with Lipid Membranes by Local pH Modulation
Sensing Small Molecule Interactions with Lipid Membranes by Local pH Modulation
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DOI：
10.1021/ac401955t
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发表时间：
2013-11-05
影响因子：
7.4
通讯作者：
Cremer, Paul S.
中科院分区：
文献类型：
--
作者：
Huang, Da;Zhao, Tao;Cremer, Paul S.
在此，我们利用基于pH调节的无标记传感平台来检测丁卡因（一种用作局部麻醉剂的带正电荷的小分子）与平面支撑脂质双层（SLB）之间的相互作用。SLB在流动池内图案化，允许在缓冲溶液中的表面上引入各种浓度的丁卡因。对含有POPC（1-棕榈酰-2-油酰-sn-甘油基-3-磷酸胆碱）的膜进行研究，得出这种小分子膜相互作用的平衡解离常数值为Kd = 180 +/-47 μ m。向SLB中加入胆固醇降低了丁卡因和双层之间的亲和力，而当加入POPE（1-十六酰基-2-（9-Z-十八烯酰基）-sn-甘油基-3-磷酸乙醇胺）时，这种相互作用加强。还用三种带负电荷的膜脂质POPG（1-棕榈酰基-2-油酰基-sn-甘油基-3-磷酸-（1'-rac-甘油）（钠盐））、POPS（1-棕榈酰基-2-油酰基-sn-甘油基-3-磷酸-L-丝氨酸（钠盐））和神经节苷脂GM1进行了研究。与纯POPC膜相比，所有三种测量都引起了表观K-d值的类似收紧。带负电荷的脂质的身份缺乏化学特异性，表明收紧主要是静电。通过与ITC测量的直接比较，发现pH调节传感器平台提供了一种简便、廉价、高灵敏度和快速的方法，用于检测推定的候选药物和脂质双层之间的相互作用。因此，该技术可能被开发为药物开发和分析的筛选。
Herein, we utilized a label-free sensing platform based on pH modulation to detect the interactions between tetracaine, a positively charged small molecule used as a local anesthetic, and planar supported lipid bilayers (SLBs). The SLBs were patterned inside a flow cell, allowing for various concentrations of tetracaine to be introduced over the surface in a buffer solution. Studies with membranes containing POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) yielded an equilibrium dissociation constant value of K-d = 180 +/- 47 mu m for this small molecule membrane interaction. Adding cholesterol to the SLBs decreased the affinity between tetracaine and the bilayers, while this interaction tightened when POPE (1-hexadecanoyl-2-(9-Z-octadecenoyl)-sn-glycero-3-phosphoethanolamine) was added. Studies were also conducted with three negatively charged membrane lipids, POPG (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)), POPS (1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (sodium salt)), and ganglioside GM1. All three measurements gave rise to a similar tightening of the apparent K-d value compared with pure POPC membranes. The lack of chemical specificity with the identity of the negatively charged lipid indicated that the tightening was largely electrostatic. Through a direct comparison with ITC measurements, it was found that the pH modulation sensor platform offers a facile, inexpensive, highly sensitive, and rapid method for the detection of interactions between putative drug candidates and lipid bilayers. As such, this technique may potentially be exploited as a screen for drug development and analysis.