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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/17853

Title: 奈米球微影術製作奈米銀顆粒陣列於表面增強拉曼散射生物感測應用
Biological application of SERS based on silver nanoparticles arrays farbricated by using nanosphere lithography
Authors: Wen-Chi Lin
Contributors: NTOU:Institute of Optoelectronic Sciences
Keywords: 表面增強拉曼散射;奈米球微影術;奈米顆粒;時間頻域有限差分法
Date: 2010
Issue Date: 2011-07-04
Abstract: 本論文為使用奈米球微影術(NSL)製作表面增強拉曼散射(SERS)基板並探討其靈敏度,我們使用直徑為430nm 至 1500nm的聚苯乙烯奈米球製作了AgFON結構,並將銀膜厚度控制在120nm,從觀測R6G分子在表面增強拉曼散射(SERS)的表現,我們發現表面增強拉曼散射增強因子隨著聚苯乙烯奈米球的尺寸變化會有最佳化的趨勢,在使用奈米球直徑為1000nm與激發波長為532nm時表面增強拉曼散射的增強因子(EF)最強為4.3×106。透過3D時間頻域有限差分法(FDTD )模擬計算AgFON結構的電場分佈,模擬結果發現當奈米球的直徑為1000nm時會有最強的侷域電場在圓球型的金屬顆粒表面,因而增強了拉曼散射的訊號。 經由調整奈米銀顆粒的大小與高度達到控制表面增強拉曼散射(SERS)的強度,使用奈米球微影術(NSL)結合反應離子蝕刻(RIE)在玻璃基板上形成堅固的奈米銀顆粒陣列,同時選擇尺寸為430nm至800nm的聚苯乙烯奈米球製作奈米銀顆粒陣列,並藉由蒸鍍不同銀膜厚度(75nm~150nm)後使用舉離法(Lift-off)將奈米球從表面移除來改變顆粒高度。當我們使用的聚苯乙烯奈米球的尺寸變小與蒸鍍的高度變高時表面增強拉曼散射的增強因子會有很強的提升,在此實驗上,當奈米球的尺寸為430nm與實際上蒸鍍的銀膜高度為96nm時表面增強拉曼散射可以提升至2×106,透過拉曼掃描我們也證明了在奈米銀顆粒陣列上存在有侷域表面電漿共振效應而放大拉曼散射的強度。 另外,我們也將此基板應用於生物量測,目前利用光學研究河魨毒(TTX)特性是很少的,我們使用奈米銀顆粒陣列與表面增強拉曼散射(SERS)技術研究河魨毒拉曼光譜,奈米銀顆粒陣列是用奈米球微影術(NSL)與舉離法(Lift-off)製作並且可以控制奈米顆粒的大小、形狀與奈米顆粒的間距。我們也利用Gauissan03模擬軟體和使用密度泛涵理論(DFT)計算出河魨毒的拉曼光譜與振動模式,而河魨毒主要的影響是河豚毒結構裡的NH2群組與人體的鈉通道(sodium channel)結合而導致人體麻痺,在此我們針對河魨毒的NH2群組分析出拉曼光譜振動模式。在SERS的實驗裡,我們可以量測出河魨毒的濃度最低為0.9ng/mL,這個結果已經和高效液相層析儀(HPLC)的靈敏度相同了,而在組織胺的實驗中,我們分別量測了L-histidine與histamine的一般拉曼光譜與表面增強拉曼光譜,而最低可以量測的濃度為10-10M,再次證明了表面增強拉曼散射感測系統的高靈敏度與即時量測等多項優點。
The dependence of nanoparticle size on surface-enhanced Raman scattering (SERS) from silver film over nanospheres (AgFON) substrate is studied. For a range of nanosphere sizes from 430-1500 nm, optimum SERS signal is obtained with a nanosphere size of 1000 nm at an excitation wavelength of 532 nm. We have clarified the physical origin of this optimization in an unambiguious way as due to resonant plasmonic excitations from 3D finite-difference time-domain (FDTD) simulations, as well as with the assistance of UV-Visible reflectance spectrum. In addition, it is demonstrated that the SERS intensity of R6G molecules adsorbed on Ag nanoparticle array can be controlled by tuning the size and height of nanoparticles. Firm Ag nanoparticle array was fabricated on glass substrate by using nanosphere lithography (NSL) combined with reactive ion etching (RIE). Different sizes of Ag nanoparticles were fabricated with seed polystyrene nanospheres from 430nm to 820nm in diameter. By depositting different thickness of Ag film and lifting off nanospheres from the surface of the substrate, the height of Ag nanoparticles can be tuned. It is observed that the SERS enhancement factor will increase when the size of Ag nanoparticles decreases and the depositon thickness of Ag film increases. An enhancement factor as high as 2 × 106 can be achieved when the size of polystyrene nanosphere is 430nm in diameter and the height of the Ag nanoparticle is 96nm. By using confocal Raman mapping technique, we also demonstrate that the intensity of Raman scattering is enhanced due to the local surface plasmon resonance (LSPR) occured in the Ag nanoparticle array. We also have the bio-sensing application by using these SERS substrates. The optical properties of tetrodotoxin (TTX), a scarce toxin with anesthetic properties, were studied using nanoparticle arrays-assisted surface-enhanced Raman scattering (SERS). The nanoparticles arrays were fabricated using nanosphere lithography and a metallic lift-off process to control the particle size, shape, and spacing in the arrays. Using density functional methods, the Raman spectrum of TTX was also calculated with Gaussian03 software. The main peaks of the spectrum are originated from the vibration of the NH2 molecule group. In the SERS experiment, we were able to measure the Raman spectrum with a TTX concentration as less as 0.9 ng/mL. This sensitivity is comparable to that from high performance liquid chromatography. In the histamine experiments, SERS bio-sensing system was been demonstrated again that has high sensitivity and real-time measurement.
URI: http://ethesys.lib.ntou.edu.tw/cdrfb3/record/#G0D95880003
Appears in Collections:[光電科學研究所] 博碩士論文

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