利用奈米材料開發感測系統

由於近年來奈米科技的快速發展，已有許多具有不同結構及性質的奈米材料可被合成出，並應用於化學、材料科學、及生物醫學等不同領域上。本論文的主要目的為結合奈米材料與表面輔助吸脫附質譜法、表面增強拉曼散射光譜及螢光光譜等分析技術以開發新穎的感測系統。第二章為利用碲化汞奈米材料作為表面輔助吸脫附質譜法之基質，並應用於蜂蜜樣品中單醣及雙醣分子之定量分析。藉由使用蔗糖素作為內標準品，此方法對單醣與及雙醣分子之定量範圍分別為0.05–30 mM及0.03–10 mM，也可成功分析蜂蜜樣品中的醣類含量。與傳統方法相比，此方法具有簡單（不需額外前處理分離）、迅速（可於30分鐘內完成分析）及良好的再現性（相對標準差小於15%）等優勢。第三章中的研究利用兩種不同金奈米材料結合表面增強拉曼散射光譜以開發對於血小板衍生生長因子的檢測方法。修飾了核酸適配體及巰基苯甲酸的金奈米粒子同時具有辨認樣品中的血小板衍生生長因子及提供表面增強拉曼散射訊號的功能。金奈米珍珠項鍊則是具有良好再現性的表面增強拉曼散射基質。當修飾了核酸適配體及巰基苯甲酸的金奈米粒子與樣品中之血小板衍生生長因子結合後，此複合體會因靜電作用力而吸附在金奈米珍珠項鍊的表面上，並生成對於拉曼散射訊號有更強的增強效果之團聚體，導致巰基苯甲酸的表面增強拉曼散射訊號增強。此靈敏（偵測極限：0.5 pM）且具有再現性（相對標準差小於15%）的方法可被應用於尿液樣品中血小板衍生生長因子之偵測。第四章則是利用牛血清白蛋白包覆之鈰／金複合金屬奈米團簇以偵測樣品中的氰化物。氰化物會蝕刻金屬奈米團簇中的金核，導致其螢光強度下降。然而在鈰離子的存在下，會導致牛血清白蛋白的結構更為鬆散，使氰化物更容易與牛血清白蛋白包覆之金核反應。故此材料可以提供更好的靈敏度（偵測極限：50 nM）及較短的反應時間（15分鐘）。此方法也被應用於外添加氰化物之湖水及飲用水樣品之偵測，證明此方法對於複雜樣品中的氰化物偵測極具潛力。在第五章中，我們利用牛血清蛋白包覆之鈰／金複合金屬奈米團簇作為可同時檢測pH值及活性氧化物質的探針，並應用於監控細胞中pH值及活性氧化物質濃度的變化。牛血清蛋白包覆之鈰／金複合金屬奈米團簇位於410 nm及680 nm的螢光分別會隨著環境pH值及活性氧化物質濃度而變化。在pH 7.0下，此系統對於過氧化氫及次氯酸鈉的偵測極限分別為0.8和3.2 μM。我們也藉由測試此系統對於Hela及HepG2兩株細胞的毒性以探討其生物相容性。此具有良好生物相容性及穩定性的系統也被成功應用於監測由氯化奎寧、地塞米松及過氧化氫造成HepG2細胞內pH值及過氧化氫濃度的變化。在第六章中我們利用可催化葡萄糖氧化反應的酵素在奈米材料表面產生高濃度的過氧化氫，並發現藉由此簡單且多功能的系統產生的過氧化氫可以選擇性的從和雙晶平面平行的{111}晶面開始蝕刻銀奈米雙晶方塊，此蝕刻過程與其生長過程十分相似。而在單晶銀奈米方塊的蝕刻實驗中，此系統會從銀奈米方塊的八個角開始蝕刻，使其逐漸轉變為球形奈米結構。此研究提供了一個可調控且具有選擇性的金屬奈米材料蝕刻技術，相信未來有機會應用於探討奈米材料合成生長機制，並增加奈米材料形貌的多元性。

關鍵字

表面輔助吸脫附質譜法；表面增強拉曼散射光譜；螢光光譜法；奈米材料；金屬奈米團簇；蝕刻

並列摘要

Because of the advance in nanotechnology, nanomaterials (NMs) with different structures and properties can be prepared and applied into different field including chemistry, materials science and biomedical applications. This thesis focused on the development of novel sensing systems by combining nanomaterials and analytical techniques including surface-assisted laser desorption/ionization mass spectroscopy (SALDI-MS), surface-enhanced Raman scattering (SERS), and fluorescence spectroscopy. In chapter 2, a SALDI-MS based assay for the quantification of monosaccharides and disaccharides in honey samples is described. By using HgTe nanostructures as matrix and sucralose as internal standard, this assay allows the quantification of monosaccharides and disaccharides in the range from 0.05–30 mM and 0.03–10 mM, respectively, and the determination of the contents of saccharides in honey samples with the advantages of simplicity (without any separation process), rapidity (<30 min), and good reproducibility (RSD<15%). In chapter 3, a SERS-based assay using two different nanomaterials have been demonstrated for highly sensitive and selective detection of platelet-derived growth factor (PDGF). Au nanoparticles (Au NPs) modified with aptamer (Apt) and 4-mercaptobenzoic acid (4-MBA) are used as selector and reporter, while Au pearl necklace nanomaterials (Au PNNs) are used as SERS substrates. The Apt/MBA-Au NPs specifically bound with PDGF, and further attached on the surface of Au PNNs and formed aggregation via electrostatic interactions, which led to the increase in SERS signals of 4-MBA. This assay can be used for the detection of PDGF in urine samples with advantages of sensitivity (LOD: 0.5 pM) and reproducibility (<15%). Chapter 4 described the detection of cyanide using bovine serum albumin-stabilized cerium/gold nanoclusters (BSA-Ce/Au NCs) as probes. CN- etched the Au cores of BSA/Ce-Au NCs and led to the decrease of the fluorescence from Au cores. On the other hand, the presence of Ce4+ ions changed the structure of BSA to a loose form and make CN- reacted with Au cores more easily, which enhanced the sensitivity (50 nM) within a shorter reaction time (15 min). The assay has also been applied to the determination of the concentrations of CN- in spiked drinking water and pond water samples, showing its great potential for the detection of CN- in complicated samples. We also applied BSA-Ce/Au NCs for the detection of ROS and pH dual probes for intracellular pH and ROS levels in chapter 5. The fluorescence of BSA-Ce/Au Au NCs at 410 nm and 680 nm are separately sensitive to pH values and ROS levels. At pH 7.0, BSA-Ce/Au NCs provides LOD of 0.8 and 3.2 μM for H2O2 and NaClO, respectively. The Biocompatibility of BSA-Ce/Au NCs has been validated in HeLa and HepG2 cells. The practicality of this biocompatible and stable probe has been validated by monitoring the intracellular pH and ROS changes inside HepG2 cells induced by chloroquine, dexamethasome, and H2O2. In chapter 6, we reported a simple and versatile system for generating highly concentrated H2O2 on the surface of nanoparticles through enzymatic oxidation of glucose. We identified that the highly localized H2O2 would lead to selective etching of Ag twinned cubes from the {111} facets parallel to the twin plane, in a fashion identical to the growth process but in the reversed order. For Ag single-crystal nanocubes, the etching would initiate from the corners to gradually transform the cubes into spheres. This study offers the opportunity to control the etching of metal nanocrystals with selectivity for elucidating the mechanism and diversifying the nanocrystals.

並列關鍵字

surface-assister laser desorption/ionization spectroscopy ； surface-enhanced Raman scattering ； fluorescence spectroscopy ； nanomaterials ； nanoclusters ； etching

參考文獻

Chapter 1

(1) Barnes, W. L.; Dereux, A.; Ebbesen, T. W. Surface plasmon subwavelength optics. Nature 2003, 424, 824–830.

(2) Shtykov, S. N.; Rusanova, T. Y. Nanomaterials and nanotechnologies in chemical and biochemical sensors: Capabilities and applications. Russ. J. Gen. Chem. 2008, 78, 2521–2531.

(3) Chiang, C.-K.; Chen, W.-T.; Chang, H.-T. Nanoparticle-based mass spectrometry for the analysis of biomolecules. Chem. Soc. Rev. 2011, 40, 1269–1281.

(4) Lane, L. A.; Qian, X.; Nie, S. SERS nanoparticles in medicine: from label-free detection to spectroscopic tagging. Chem. Rev. 2015, 115, 10489–10529.

國際替代計量

利用奈米材料開發感測系統

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