【作者】 范翊；

【导师】 申德振； 李亚军；

【作者基本信息】 中国科学院研究生院（长春光学精密机械与物理研究所） ， 凝聚态物理， 2003， 博士

【摘要】 从材料科学的角度来看，细胞膜是一种完美的结构。其高度有序的自组装结构为细胞提供了所有必不可少的功能，如：分子识别、质子泵、能量传递和信号传输。具有特殊功能特性的人造膜结构的设计已成为一门新兴的研究领域。 本论文设计出一种简单、直接的方法来探测分子识别过程。利用聚二乙炔LB膜的变色特性，采用合成的一系列糖脂(MPDA_1-7)，与10，12-二十五碳双炔酸（简称PDA）混合，详细研究了聚合的MPDA/PDA LB薄膜、泡囊与细菌的分子识别作用，并采用这种直接比色法检测了TiO₂纳米粒子的杀菌效果。结果表明： 在MPDA/PDALB薄膜的制备过程中，pH值、温度、混合比例对成膜质量有很大影响。在pH=5.6，亚相温度为14℃，MPDA_1-3，5与PDA的混合比例为1：20的条件下，成膜质量较好。但MPDA_6-7不溶于常用有机试剂，不能在本研究中采用。研究了MPDA_1-5的分子识别特性。MPDA_1-3与大肠杆菌K12均可发生分子识别，导致薄膜颜色由蓝变红，同时薄膜的UV-visible吸收光谱最大吸收峰从蓝膜时的640nm，蓝移到红膜时的540nm。通过比较MPDA1-4的比色响应特性，我们发现4种甘露糖衍生物中MPDA₃具有较好的变色响应分子识别的能力和较低的热效应改变值。这种分子识别是不可逆的，并且为特异性识别。对薄膜进行分子识别的动力学过程进行了探讨。理论推导出，一个大肠杆菌与2个糖脂分子结合。用Raman光谱研究了PDA变色响应的分子机理。 研究丁MPDA₃/PDA（1：20）泡囊与大肠杆菌的分子识别特性。确定最佳超声温度为72-76℃，超声时间30min，超声后需要在4℃放置48小时使泡囊闭合。比较了不同的稀释溶液对泡囊光学特性的影响，发现生理盐水的影响最小。探索了泡囊与大肠杆菌的反应动力学过程，发现泡囊与大肠杆菌反应2min后，基本达到饱和。计算了不同细菌浓度下的比色响应值。探索人工环境下，不同金属阳离子对分子识别的影响。发现Cd²⁺＞Ca²⁺＞Ba²⁺＞Mg²⁺＞Fe³⁺＞Cu²⁺。其中Fe³⁺、Cu²⁺的存在对分子识别起抑制作用，Ba²⁺、Mg²⁺的影响不大，而Cd²⁺、Ca²⁺的存在对泡囊的分子识别作用的影响非常大，其中Cd²⁺的存在使泡囊的灵敏度提高一倍多。用FTIR、Raman对泡囊与细菌的识别进行了表征，发现聚合物由乙炔结构范诩:博士学位论文向丁三烯结构转变。 用直接比色法检测了胶体TIO:的杀菌能力。制备出中性的TIO:胶体，发现与大肠杆菌KIZ预培养lh、幅照1h可杀死所有大肠杆菌K]2（CR值为6.6%，与背底热效应值相同）。比较了悬浮液与胶体TIOZ的光催化杀菌能力，结果表明我们制备的胶体TIOZ纳米粒子是一种较强的杀菌剂。 最后利用电化学方法一循环伏安法研究了金电极上自组装硫醇一LB薄膜双分子层与大肠杆菌K12培养后电化学性质的变化。研究结果表明MPDAZ/PDA薄膜与大肠杆菌培养后，其峰电流的响应值变化很明显，且响应值随细菌浓度的增加而降低。可能主要是由于仿生膜结构的变化，阻碍了电极表面的氧化还原作用，从而引起明显的峰电流变化。更多还原

【Abstract】 Cell membranes are perfect structures from a materials science point of view. These highly organized, self assembly structures provide indispensable functions for cell such as molecular recognition, signal transduction and energy conversion. The design of smart artificial membrane with special function characteristic is an emerging field of research.In this thesis, we design a simple and direct method to detect molecular recogniton interactions. A series of glycolipid （MPDA 1-7） were synthesized, mixed with 10,12-pentacosadiynoic acid （PDA）. The recognition of MPDA/PDA mixed LB films and vesicles on E.coli K12 was studied in detail. The bactericidal effect of nanoparticles of TiOi photocatalysist was tested by this directly chromatic method. The experiments show:Properties of MPDAi/PDA monolayer were greatly affected by pH value, temperature of subphase and mixed ratio of MPDAi and PDA. When subphase temperature is 14 ℃, pH is 5.6 and MPDAj.3, 5/PDA is mixed in a ratio of 1:20, the quality of the monolayer is better. But MPDA6-7 does not dissolve in common reagent, it can’t be used in this work. The properties of MPDA 1-5 are studied in detail. MPDA 1-3 all can be recognized by E. coli K12, colorimatric response （CR） is 31%（MPDAi/PDA）, and MPDA/PDA film changes color from blue to red. The absorption maxima at 640nm on UV-visible absorption spectroscopy of the film shift to 540nm. Comparing the chromatic properties MPDAs is better than other MPDA, and the background is low. This kind of chromatic molecular recognition is irreversible and specific. Kinetics of the recognition process was discussed. We estimate that Escherichia coli cell can only bindtwo MPDAs molecules. Mechanism of PDA chromatic response to molecular recognition was investigated by Raman spectroscopy.Chromatric properties of MPDAs / PDA （1:20 in volume） vesicles were studied. High quality of vesicles were prepared by sociating for 30 min at 72-76℃ and placing for 48 hours at 4℃ to make vesicles close. Comparing influence of the different dilution to the optical characteristic of vesicles, the results show that the change of salt water on UV-visible absorption spectroscopy is lowest. Kinetic experiments shown that the color change induced by the addition of an aliquot of E.coli reaches a plateau after 2min. Colorimetric response （CR） of vesicles at different concentration were calculated. The influence of different cation on molecular recognition was investigated in vitro. The results show: Cd2+> Ca2+> Ba2+> Mg2+> Fe3+> Cu2+. Fe3+, Cu2+ can inhibit the recognition, and the exist of Ba2+or Mg2+ does not influence the recognition, but the exist of Cd2+ or Ca2+ can improve the molecular recognition or increase colorimetric degree of vesicles. Especially Cd2+, the colorimetric response is double. The binding of vesicles on E.coli was characterized by FTIR and Raman spectroscopy.Bactericidal effect of colloid TiO₂ was detected by directly chromatic method. Neutral colloid TiO₂ was prepared, we have found that a suspension of E.coli K12 and colloid TiO₂（l:4） were pre-incubated for 1 h, and irradiated for 1 h （UV 365nm）, all of bacteria were killed （CR is to 6.6%, which is equal to background）. The colloid TiO₂ we prepared is a stronger photocatalysis disinfectant.Finally, cyclic voltammetric method was used to detect the molecular recognition of E.coli K12 on mannose in polydiacetylene derivative supported on the self-assembled monolayers of octadecanethiol on a gold electrode. After the electrode was incubated with E.coli K12 for 3min, the peak current gradually decreased and appeared plateau-shaped at potential past the redox potential of probe molecules and the current decreased exponentially after 5min. The amperometric signal decreased quickly with increasing concentration within the range of Ixl08 to 7x108 cells/mL. These changes were attributed to the decrease of defect density within the bilayer of MPDA2/PDA.更多还原