Development of Novel Synthetic Bilayer System Possessing Chemical Information Transduction and Amplfication Ability

生物膜由脂双层和膜蛋白组成，是将化学信号转化为电信号的换能器。本研究的目的是开发模拟生物膜的新型分子识别和信息转导系统。主要研究内容如下：(1)设计并制备了含硫醇的磷脂。采用乙醇化学吸附的方法在金电极上制备了单分子膜，并用循环伏安法对其性质进行了表征。改变溶液的pH值可以控制铁氰化物和二茂铁铵在电极单分子膜中的渗透或扩散。电极对碱土金属离子有响应。(2)对将分子信息转换为电信号或电化学信号的双层器件的设计和制作进行了基础性研究。图案化电极上的季铵盐脂在双层膜相变以上加热时，其阻抗和电容发生了剧烈的变化。然而，初级铵类脂不表现出这种相变依赖性。尽管单链季铵盐膜的转变热很小，但在阻抗测量中，单链季铵盐膜表现出与双链脂类相同的T_c依赖关系。研究了生物脂膜的阻抗特性。通过阻抗的Cole-Cole图分析，对所得结果的分子机理进行了分析。

Biological membranes are composed of lipid bilayer and membrane proteins and act as transducers which convert chemical signals to electrical signals. The aim/purpose of this study is to develop novel molecular recognition and information transduction systems mimic to biological membranes. The summaries are as follows.(1) A mercaptan-containing phosphate lipid was designed and prepared. Monolayer of the lipid was fabricated on gold electrodes via chemisorption from ethanol and their properties were examined by cyclic voltametry. The permeation or diffusion of ferricyanide and ferrocene ammonium into the monolayer on the electrode could be controlled by changing pH of the solution. The electrodes were found to response to alkali earth metal ions.(2) Fundamental examinations on design and fabrication of bilayer devices which transduce molecular information to electric or electrochemical signals were conducted. Quaternary ammonium lipids on patterned electrodes showed drastic change in impedance and capacitance upon heating above phase transition of bilayers. However, primary ammonium lipids exhibited no such phase transition dependence. Despite the very small transition enthalpy, single chain quaternary ammonium film showed the same Tc dependence in impedance measurements as those with double chain lipids. Impedance characteristics of biological lipid films were also investigated. Molecular mechanisms for the obtained results were analyzed by cole-cole plot analyses of impedance.