兰州大学机构库 >生命科学学院
光响应DNA双亲分子在液晶-水相界面的组装行为研究
Alternative TitleStudy on the Assembly Behavior of Photo-Responsive DNA Amphiphile at the LC-Aqueous Interface
安小苹
Thesis Advisor王锐
2017-04-18
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
KeywordDNA 双亲分子 液晶 组装 调控
Abstract

液晶是一类介于固态和液态之间的新的物质相态。自从1888年首次发现液晶,此后液晶广泛地存在于日常生活中,例如电子显示器。此外,过去近二十年的研究发现,液晶还可用作优良的传感材料,这主要是基于液晶固有的短程分子-分子相互作用和长程取向有序性质,可以将微纳米尺度的分子相互作用放大和传导成宏观可测的光学信号。因此,开发和发展了免标记、低成本、低耗能、可实时观测的液晶传感/检测平台。

借助液晶传感平台研究分子间相互作用的报道主要集中于传统的双亲分子、核酸、蛋白质、细菌和病毒等。然而,这类功能界面通常缺少特异性和选择性,限制其进一步应用。值得注意的是,DNA双亲分子具有DNA的可设计性,可以精确地控制其序列和长度,也可以进一步地用功能性基团修饰,因此有望提高液晶传感系统的响应性和选择性。其次,对于组装有双亲分子的液晶界面进行调控往往依赖于引入新的化学物质,而利用远程、清洁的光刺激进行调控将扩大其应用范围,但目前却鲜有报道。

因此,本论文的研究重点是设计一类含偶氮基团的光响应DNA双亲分子(简称Azo-DNA),研究其在平面和具有曲面的液晶-水相界面的组装行为,并进一步探索利用光对界面组装进行调控。通过初步实验发现纯的Azo-DNA在一系列浓度条件下,在平面液晶-水相界面均未产生可观测的液晶光学信号的改变,这表现出Azo-DNA与传统双亲分子不同的组装行为:Azo-DNA本身具有较强的组装能力,因此难以解组装并与液晶相互作用。随后,我们尝试了在Azo-DNA中掺杂磷脂DLPC以促进Azo-DNA的解组装。发现其在平面液晶-水相界面的共组装,结果产生了不同于Azo-DNA或DLPC单独组装时的光学织构。随后,我们通过同时荧光标记Azo-DNA和DLPC的方法,原位地观察Azo-DNA和DLPC在液晶-水相界面的分布情况。对于具有曲面的液晶-水相界面(液晶液滴),强的外界超声作用可以有效地破坏Azo-DNA组装体,并促进其进一步组装到具有曲率的、高表面能的液晶液滴表面。利用偶氮基团顺式和反式构象的分子极性差异,我们成功地将Azo-DNA双亲分子组装到液晶液滴表面,并对液晶液滴进行了聚集和分散的两次循环的可逆调控,为实现多次可逆的光调控液晶-水相界面的工作打下基础。

Other Abstract

Liquid crystals (LCs) are a new class of materials state that can exhibit characteristics between the solid and the liquid state. LCs have quickly become widespread in our daily life since 1888 and are well known for their applications in electronic display technology. In addition, in the past two decades, LCs have been investigated as excellent sensing materials, with the intrinsic properties of short-range molecule-molecule interactions and long-range orientational communication that can be used to amplify and transform micro- and nanoscale molecular interaction into macroscopic measurable optical signals. Hence, they provide a label-free, low-cost, low power consumption and real-time detection platform.

Previous studies of the molecular interactions using LCs-based sensing platforms mainly focused on traditional amphiphiles, nucleic acid, proteins, bacteria and viruses. However, these kinds of functional interface have low specificity and selectivity. It is worth noting that for DNA amphiphiles, the DNA can be programmed to control its sequence and length, to be further modified by functional groups. So it is expected to improve the responsiveness and selectivity of the LC-based detection system. On the other hand, the regulation of the LC interface with the amphiphiles assembly often relies on the introduction of additional chemical substances. On the contrary, using remote and clear light stimulus to control the LC interface will provide a potential expanded scope of application, but relevant reports are few.

Therefore, the research focus of this article was to design a type of photo-responsive azobenzene-containing DNA amphiphiles (named Azo-DNA), and studied its assembly behavior at planar and cambered LC-aqueous interfaces. Additionally, the use of light to regulate the assembly behavior of the DNA amphiphiles was investigated. The preliminary experiment results showed that for a series of concentrations, Azo-DNA did not cause any optical signal change at the planar LC-aqueous interface. This differed from the traditional amphiphiles: as the assemblies of Azo-DNA are too stable to disassemble, so it is difficult for them to interact with LCs. Then we tried to mix the Azo-DNA with DLPC to promote its disassembly, for which some special optical textures were obtained that differed from the individual ones. Subsequently, we used dual- fluorescent labelling to confirm the detailed assembly behavior in suit. For the cambered interface (LC droplets), strong external ultrasonic waves effectively caused disruption of the Azo-DNA assemblies, then promoted the assembly at the LC droplets surfaces, which were cambered and with high surface energy. We successfully achieved the assembly of Azo-DNA at the LC droplets interface as well as reversibly controlling the assembly/disassembly of the LC droplets, which based on the different polar properties for trans and cis azobenzene. Currently, two reversible cycles have been achieved, laying the foundation for future work to extend this research further.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221299
Collection生命科学学院
Recommended Citation
GB/T 7714
安小苹. 光响应DNA双亲分子在液晶-水相界面的组装行为研究[D]. 兰州. 兰州大学,2017.
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