Dynamic behavior analysis of ion transport through a bilayer lipid membrane by an electrochemical method combined with fluorometry
Dynamic behavior analysis of ion transport through a bilayer lipid membrane by an electrochemical method combined with fluorometry
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电化学结合荧光法分析双层脂膜离子传输的动态行为
DOI：
10.1039/d0an00222d
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Yoshida Yumi
中科院分区：
文献类型：
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作者：
Omatsu Terumasa;Hori Kisho;Naka Yasuhiro;Shimazaki Megumi;Sakai Kazushige;Murakami Koji;Maeda Kohji;Fukuyama Mao;Yoshida Yumi
为了研究离子物质通过双层类脂膜（BLM）的转运，提出了一种电化学结合荧光法。在该方法中，荧光离子通过BLM的转运被检测为跨膜电流和荧光强度同步扫描膜电位的动态变化。通过利用共聚焦荧光显微镜在靠近平面BLM的局部区域中测量荧光强度。电化学方法与荧光测定法相结合，使得有可能仅分析与其他共存离子的运输不同的目标荧光离子的运输。利用所提出的电化学方法，研究了疏水性荧光阳离子（罗丹明6G+，R6G+）和相对疏水性阴离子（BF 4 −）引起的离子迁移。电化学方法结合荧光法表征了R6G+的跨膜电流。R6G+转运的膜电导与分布在BLM烃介质中的R6G+和BF 4 −的浓度成比例增加，这是通过脂质体提取实验估计的。这些结果表明，在BLM中的水相的阳离子和阴离子的分布主要控制通过BLM的离子传输的膜电导。
To examine the transport of an ionic substance through a bilayer lipid membrane (BLM), an electrochemical method combined with fluorometry was proposed. In this method, the transport of a fluorescent ion through the BLM was detected both as the transmembrane current and the dynamic change of fluorescence intensity synchronizing scanning membrane potential. The fluorescence intensity was measured in the local area close to the planar BLM by utilizing a confocal fluorescence microscope. The electrochemical method combined with fluorometry makes it possible to analyze only the transport of a target fluorescent ion in distinction from the transport of other coexisting ions. With the proposed electrochemical method, the ion transport caused by both a hydrophobic fluorescent cation (rhodamine 6G+, R6G+) and a relatively hydrophobic anion (BF4−) was examined. The electrochemical method combined with fluorometry characterized the transmembrane current as the transport of R6G+. Membrane conductance for the R6G+ transport increased proportionally to the concentrations of R6G+ and BF4− distributed in the hydrocarbon medium of the BLM which were estimated by extraction experiments with liposomes. These results show that the distribution of a cation and an anion from the aqueous phase in the BLM predominantly controls the membrane conductance for ion transport through the BLM.