金奈米雙錐體/奈米棒之自組裝用於螢光增強研究

Abstract

金奈米材料的尖端因表面電漿共振(Localized Surface Plasmon Resonance, LSPR)，在尖端處擁有較強之電場增強的有去特性。對由於金奈米顆粒表面的保護基可導致其親疏水性的改變，本研究利用不同的硫醇作為保護基修飾金奈米材，一方面控制其表面之親疏水性，另一方面可控制其懸浮於極性與非極性溶液的界面間，將金奈米材料在玻璃基板等平面上進行自組裝排列。利用掃描式電子顯微鏡觀察排列的情況，可以發現金奈米雙錐體的端點指向中心，排列成一類似寄木細工的圖樣（Yosegi patterns）。此一自組裝方法，成功的使金奈米雙錐體的端點相互靠近，並預期在金奈米材料端點對端點的間隙處，會有更強的近場電場增強。本研究中，以近紅外光螢光分子（near-infrared fluorescent dyes）的螢光增強作為研究的重點，選用Streptavidin-IR800作為螢光染劑，藉由金奈米顆粒的自組裝（self-assembly）技術排列出有序的金屬奈米薄膜圖樣，使其電場增強的性質能更加突出，相較於單純的有玻璃基板能夠有效的提升螢光的訊號強度1477倍。此一技術將使金奈米材料未來在光學及奈米生醫檢測方面有更多的應用與發展機會。

Because of the localized surface plasmon resonance (LSPR), the gold nanoparticles show strong electric field enhancement properties, which many researchers are interested in. In this study, different thiols molecules which can control the hydrophilicity and hydrophobicity of the gold nanoparticles were used as the capping ligands to modify the surface. Furthermore, we can even control the the location of the nanoparticles to suspend in interface between polar and non-polar solutions. Then, the gold nanoparticles were dropped on a glass substrate or other planes for their self-assembly. Using the scanning electron microscope to observe the arrangements, we can find that the end-to-end arrangements of the gold nanoparticles, which are similar to the Yosgi patterns. The method successfully manipulated the end-to-end arrangement, which were close to each other by self-assembly. Strong near-field electric field enhancement can be generated in the space between the end-to-end gaps of the gold nanomaterials. In this study, we focused on the fluorescence enhancement of near-infrared fluorescent dyes (Streptavidin-IR800). After self-assembly, the gold nanoparticles showed a well-arranged pattern in this film, which makes the enhancement of the electric field, and effectively signal intensity of fluorescence by 1477 times. This method will enable gold nanoparticles to have more applications and opportunities in optics and nanomedicine in the future.