本文選題：納米氣泡 + 原子力顯微鏡(AFM)�。� 參考：《中南林業(yè)科技大學》2017年碩士論文

【摘要】：納米尺度下氣體在固液界面上的聚集行為被證明對固液界面性質有著重要的影響,并且在流體動力學、表面化學、膠體化學、環(huán)境和生命科學等眾多領域具有廣闊的潛在應用價值,引起了科學工作者極大的關注和重視。關于如何解釋界面納米氣泡的穩(wěn)定存在機理以及相比于宏觀尺度下較大的接觸角是目前納米氣泡研究的爭議中心和亟需解決的核心問題。界面納米氣泡的研究離不開基底。從理論上講,上述兩個關鍵問題都直接涉及產(chǎn)生納米氣泡的基底,因此基底的性質是影響納米氣泡界面性質不可忽略的關鍵因素之一。一方面,氣泡在不同基底上的形成,穩(wěn)定性以及界面形貌都可能不同;另一方面,受基底性質的影響,不同的基底得到的納米氣泡的接觸角也可能不一樣。但目前各個實驗組研究的基底都相對單一,生成納米氣泡的大小和數(shù)量的可控性和重復性差,所以,迫切需要找到一種通過控制基底的界面結構和性質來控制納米氣泡的大小和數(shù)量的方法來進一步研究納米氣泡的基本物理性質,形成機理和穩(wěn)定機制等關鍵問題�；谝陨夏康�,本論文利用先進的微納米加工技術—電子束光刻(Electron Beam Lithography,EBL)直寫技術制備不同尺度、和不同疏水性的納米周期性結構基底。通過先進的納米觀測技術—原子力顯微鏡(Atom Force Microscopy,AFM)技術對納米氣泡在周期性結構基底上的吸附行為和界面特性的研究發(fā)現(xiàn)納米氣泡主要吸附于周期性結構上的疏水區(qū)域且受限于疏水結構的尺寸進而引起接觸角的變化。與此同時,相應的分子動力學模擬也進一步證實了疏水結構對納米氣泡的限制作用,使得實驗與模擬能夠相互印證,相互支持。這將為實現(xiàn)通過基底的性質來人為調控納米氣泡的生成和界面吸附的目的,為探索納米氣泡在微流體器件方面的應用提供實驗基礎。生理惰性氣體進入人體后與一些生物分子或者離子通道結合進而對許多生命過程發(fā)揮著重要的作用,如生物麻醉,神經(jīng)、組織保護等,然而人們對其內在的作用機理卻是知之甚少。分子動力學研究發(fā)現(xiàn)聚集態(tài)的氮氣分子可以特異性地與蛋白的活性位點結合,而游離的氮氣分子卻不具有這一特異性結合效應。隨著納米氣泡的發(fā)現(xiàn),這似乎為我們提出了一個新的思路。惰性氣體分子能夠在蛋白分子的疏水基團發(fā)生特異性結合形成氣泡從而使得這些基團的生物功能被屏蔽失效,當氣體被清除掉后,相應的生物功能可能會恢復。基于這一設想,我們通過上海光源BL15U同步輻射硬X射線熒光吸收譜和熒光成像技術對Xe和Kr在胃蛋白酶上的吸附情況進行了研究,結果表明Xe和Kr在含胃蛋白酶的溶液中的含量都比不含胃蛋白酶的水溶液高。納米粒子追蹤實驗結果表明含Xe的胃蛋白酶溶液中的粒子濃度比不含Xe的胃蛋白酶溶液高,這可能是由于Xe分子與胃蛋白酶結合形成較大粒子進而被捕獲。分子動力學結果表明,不同的氣體分子可以在胃蛋白酶分子上特異性地聚集為氣泡。相關的蛋白活性實驗也表明加入N2,Xe,Kr的胃蛋白酶溶液,其蛋白活性降低,經(jīng)脫氣處理后,蛋白活性恢復。這就為我們深入理解氣體分子的生物效應提供了新的思路。
[Abstract]:The aggregation behavior of gas on the solid-liquid interface in nanoscale has been proved to have an important influence on the properties of the solid-liquid interface, and has a broad potential application value in many fields, such as hydrodynamics, surface chemistry, colloid chemistry, environment and life science. It has aroused great attention and attention of the scientific workers. The stable existence mechanism of the surface nanoscale and the larger contact angle compared to the macro scale are the center of dispute and the key problem to be solved at present. The research on the interface nanoscale can not be separated from the substrate. In theory, the above two key problems are directly related to the formation of the basement of the nanoscale bubble, so the base Property is one of the key factors that can not be ignored. On the one hand, the formation, stability and interface morphology of bubbles may be different on different substrates. On the other hand, the contact angles of different substrates may be different by the effect of substrate properties. As the substrate is relatively single, the size and quantity of the nano bubbles are controlled and the reproducibility is poor. Therefore, it is urgent to find a method to control the size and quantity of the nanoscale by controlling the interface structure and properties of the substrate to further study the basic physical properties, the formation mechanism and the stability mechanism of the nanoscale. Based on the above purposes, this paper makes use of advanced micro nano processing technology, Electron Beam Lithography (EBL) direct writing technique to prepare different scales and different hydrophobicity nanoscale periodic structure substrates. By advanced nano observation technology, atomic force microscopy (Atom Force Microscopy, AFM) technology for nano bubbles The study on the adsorption behavior and interfacial properties on the periodic structure shows that the nano bubbles are mainly adsorbed on the hydrophobic region on the periodic structure and are limited to the size of the hydrophobic structure and then cause the change of the contact angle. At the same time, the corresponding molecular dynamics simulation also further confirms the limitation of the hydrophobic structure to the nanoscale. The experiment and simulation can confirm each other and support each other. This will provide an experimental basis for the purpose of realizing the formation and adsorption of nano bubbles by the nature of the substrate, and to explore the application of the nano bubbles in the micro fluid devices. It also plays an important role in many life processes, such as biological anaesthesia, nerve, tissue protection, and so on. However, people know little about its intrinsic mechanism. Molecular dynamics studies find that the nitrogen molecules in the aggregation state can specifically combine with the active sites of the protein, while the free nitrogen molecules do not have this one. Specific binding effect. With the discovery of nanoscale, this seems to give us a new idea. The inert gas molecules can specifically bind to the hydrophobic groups of the protein molecules to form bubbles so that the biological functions of these groups are shielded and invalidation. When the gas is removed, the corresponding biological function may be restored. Based on this idea, we have studied the adsorption of Xe and Kr on pepsin by BL15U synchrotron radiation hard X ray fluorescence absorption spectrum and fluorescence imaging technology of the Shanghai light source. The results show that the content of Xe and Kr in the solution containing pepsin is higher than that without pepsin aqueous solution. The concentration of Xe in pepsin solution is higher than that of a pepsin solution without Xe, which may be due to the formation of larger particles of Xe molecules with pepsin and then captured. Molecular dynamics results show that different gas molecules can specifically gather as bubbles on the pepsin molecules. Related protein activity experiments It also showed that the protein activity of pepsin solution in N2, Xe and Kr was reduced, and the activity of protein was restored after degassing, which provided a new idea for us to understand the biological effects of gas molecules.
【學位授予單位】：中南林業(yè)科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：Q68
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本文編號：1901898