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標題: | 具觸發感應之自組裝碳量子點 Stimulated Responsive Carbon Dot Assemblies |
作者: | 程祖衡 Tzu-Heng Chen |
指導教授: | 張煥宗 Huan-Tsung Chang |
關鍵字: | 碳點,自組裝,脂體, carbon dot,self-assembly,lipid, |
出版年 : | 2019 |
學位: | 博士 |
摘要: | 近年來許多奈米材料被發現具有特殊的光學、電學、催化等性質,然而這些微小的粒子常常不適用現有的製程技術而無法被廣泛的應用,因此開發操控奈米材料在空間分布的技術成相當關鍵。自組裝為一種組合物質的科學,基於簡單的規則對材料進行預先編成,在自發性的狀況下由無序的結構轉為有序堆疊。在自然界中結晶、蛋白質或DNA的折疊乃至於病毒與細胞的組成、分裂等行為都屬於自組裝過程。近年來自組裝技術被發現可以操控從分子尺寸到巨觀尺度的排列,因此受到許多的重視,特別是奈米自組裝技術,在科睿唯安(原湯森路透)根據學術資料庫統計發表的”2017研究前沿”中列為為20種值得關注的研究主題。在自然界中的自組裝物質中,脂質分子做為細胞胞器構成的主體,具有最簡單的結構卻能經由相轉換或與膽固醇等其他分子等組合,達到非常繁雜的環境響應與調控,擬態此種結構將允許材料擁有類似的環境響應組裝性質,然而擬態這種自組裝分子需要將奈米材料的表面進行精準的非等向性的修飾,這在奈米技術上還有待突破。本論文的第二章基於這個技術上的缺漏進行突破,開發適用於碳量子點的非等向性修飾技術,成功的精準調控碳量子點的表面官能基與形貌,並揭露這種脂質擬態碳量子點的自組裝行為,經過簡單的環境調控分別可具有彈性體、微脂體、水凝膠與多面體等不同的結構;在第三章中,我們針對前段所提及的碳量子點微脂體的光學性質進行探討。我們發現這種碳量子點的螢光性質可以經由簡單的利用紫光(λ=405 nm)與綠光(λ=530 nm)進行重複的開關,配合碳量子點微脂體的高亮度與光穩定性,這種光制開關的開關對比(on/off contrast)與可逆性都大幅優於現今被使用的光制開關螢光物質,本章中除了探討這種材料的光制開關機制與效能,也利用這種光制開關的性質製做光制微影(photoswitching micropattern);本論文第四章則進一步揭露這種碳量子點微脂體在光照下產生的相轉換可以使之對基材產生作用力,進而利用這種光敏感的反應,可以精準的將碳量子點圖案化產生微影(micropattern),在此也發現,碳量子點微脂體在表面上的延展(spreading)除了類似於微脂體受到與基材表面作用力的影響外,同時也受到光照的調控,最後,結合黃光微影術(photolithagraphy)與前章所述的光制開關,搭配上碳量子點的激發依賴螢光(excitation-wavelength-dependent-emission ),製造可由光開關複雜的彩色螢光微影。 “The science of things that put themselves together”—self-assembly is a process through which an ordered structure forms spontaneously from disordered building blocks. This process is common in nature; for example, in crystallization, the folding of proteins and DNA, and the structuring and division of cells and viruses. Since the development of nanoscience, nanomaterials with numerous unique optical, electrical, and catalytic properties have been developed. However, the existing techniques for synthesis are not feasible or adaptable for nanoscale materials. Recently, a self-assembly technique was highlighted as being feasible for manipulating materials of various scales, from molecules to macroscale materials. Clarivate Analytics lists nanomaterial self-assembly as one of the top 20 interesting topics in their report entitled 2018 Research Fronts. The current self-assembly nanomaterials mostly mimic other self-assembling materials or are natural self-assembly materials. For instance, the DNA origami technique enables the design of arbitrary nanoscale three-dimensional structures. Lipids, which form the main skeleton of cell organelles, are simple in structure but can perform complex environmental responses or regulation through a phase transition and in combination with other molecules. Mimicking self-assembly using nanomaterials is not an easy task. To mimic these structures, a new technique is required for precise and anisotropic control of surface capping and geometry. On this basis, the second chapter of this thesis focuses on the development of anisotropic modification of carbon dots (C-dots) into a lipid-mimicking structure. The results demonstrate that highly precise control of surface modification can be achieved, enabling the synthesis of a lipid-mimicking C-dot structure. The self-assembly nature of this lipid mimicking was also uncovered in this research. Through simple modulation, lipid-mimicking C-dots can assemble into elastomer, liposome, hydrogel, and polyhedron structures. The third chapter describes the optical properties of C-dot liposomes. The photoluminescence of C-dot liposomes can be turned off and then on under photoirradiation at wavelengths of 510–540 nm and 365–420 nm, respectively. As for previously reported C-dots, the C-dot liposomes emit various colors when excited at different wavelengths. The C-dots have great stability and high contrast, and images of individual C-dot liposomes reveal that photobleaching is negligible. Using a simple photolithographic approach, micropatterns of C-dot liposomes that emit different colors were fabricated. In the fourth chapter, a direct photodeposition technique is proposed for the first time; this technique can be used for the fabrication of micropatterns of C-dot liposomes on glass substrates. Unlike in most photolithographic approaches, prepatterned substrates are not required when fabricating a micropattern of C-dot liposomes under photoirradiation at 365 nm through a photomask. The surface properties of the substrate were discovered to play a critical role in determining the microstructure of the deposited C-dot liposomes. The C-dot liposomes retain their vesicle structure and are spread on the surfaces of substrates with negative and positive charges, whereas they are completely spread on a hydrophobic surface. To demonstrate the merit of the proposed method of direct photodeposition of C-dot liposomes, micropatterns were fabricated of Taiwan’s tourism logo and Henri Matisse’s painting Icarus with multiple emission colors. An animation of the Icarus micropattern is provided to exhibit the interesting photoswitching and multiple emission colors of the C-dot liposomes. The simple and direct photodeposition approach proposed herein opens a new avenue for fabricating nanomaterial-based micropatterns. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/77443 |
DOI: | 10.6342/NTU201900008 |
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顯示於系所單位: | 化學系 |
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