螢光奈米感測器開發

Abstract

螢光奈米材料具有高靈敏度、專一性及高穩定性，故在環境分析、生物感測器、食品安全及顯影技術中具有潛力。第一部分研究由組氨酸添加各種鹵化物以簡單、新穎且環保的電化學方法合成碳點。鹵化物在碳點的形成中起兩個重要作用；控制反應速率和表面狀態。我們通過傅里葉變換紅外光譜、循環伏安法、電化學阻抗譜和 X光電子能譜結果驗證了銅離子與碘離子碳點表面配體（咪唑和組氨酸）相互作用。在 0.8 mM 碘離子的條件下，碘離子碳點對銅離子的選擇性高於被測金屬離子（如汞離子和銀離子）。此方法在訊雜比為 3 時對銅離子的偵測極限為 0.22 µM，並通過分析自來水、湖泊和海水樣品來驗證其實用性。 在第二部分中，與水溶性碳點相比，疏水性碳點的性質和應用很少被提及。在這項研究中，採用一鍋法、簡單的化學氧化方法在室溫下將濃硫酸及三酸甘油脂 (triolein, TO) 合成疏水碳點 (TO-C dots)。銅葉綠素鈉 (SCC) 通過光誘導電子轉移淬滅 TO-CD 螢光。在 400 nm 激發下，TO-C dots 在 500 nm 處的螢光強度顯示出對 1.0–10 M 範圍內的 SCC 濃度的線性相關，偵測極限為 0.61 M。調味飲料中 SCC 的定量顯示回收率為 98-103%，相對標準偏差小於 6.5%。通過在氫氧化鈉水解，疏水性 TO-C dots 可以簡單地轉化為親水性 TO-C dots。親水性 TO-CD 上磺酰基的存在增強了其對銅離子的配位能力，導致螢光猝滅，從而可以檢測銅離子，其偵測極限為 0.21 M 和線性範圍為 0.5-10 M。親水性 TO-CD對銅離子具有高選擇性（耐受性至少是其他金屬離子的 10 倍）。該測定已通過加標土壤樣品的分析得到驗證，銅離子的回收率為 97.8-99.0%，相對標準偏差低於 2.0%。表面可調式的TO-CD展示了它們在快速偵測環境樣品中的銅離子和食品中的 SCC 方面的潛力。 在第三部分中，通過水熱法合成間苯二胺-抗壞血酸碳奈米粒子 (mPA CNPs)，作為一種新型螢光感測器（量子產率 = 10%）用於偵測 pH 和次氯酸鹽。間苯二胺對於 pH 值和次氯酸鹽的反應性而被選為 CNPs 的主要成分。同時，引入了具有許多含氧基團的抗壞血酸以提高水溶性和增強反應性。因此，mPA CNPs可以通過自身螢光變化作為 pH 感測器和在中性 pH 下作為次氯酸鹽感測器。所製備的 mPA CNP 在 pH 5.5 至 8.5（R2 = 0.989）的 pH 範圍內以及次氯酸鹽的 0.125-1.25 M 濃度範圍內（R2 = 0.985）表現出線性螢光響應。在中性 pH 條件下，次氯酸鹽的檢測限 (LOD) 計算為 0.029 M。此外，mPA CNPs 還能應用於細胞中pH及次氯酸鹽濃度的成像。 在最後一部分中，聚合物在穀胱甘肽 (GSH) 輔助下可用於製備穩定的螢光金奈米團簇 (Au NCs)。 GSH 為還原劑，而聚合物為模板以穩定形成的 Au NC。製備聚合物模板 GSH-Au NCs 的最佳 pH 值為 11.0。在螢光強度和穩定性方面，聚二烯丙基二甲基銨 (PDDA) 比聚苯乙烯磺酸鹽 (PSS) 更適合製備 Au NCs。硫化氫與金團簇表面反應形成硫化金使 PDDA/GSH-Au NCs 的螢光淬滅。 PDDA/GSH-Au NCs 對硫離子的線性檢測範圍為 1-10 M，偵測極限（訊雜比 = 3）為 0.32 M。PDDA/GSH-Au NCs 在高鹽度環境下保持穩定，已應用於溫泉水樣品中硫化物離子的定量，具有良好的準確度和回收率。

Fluorescent nanomaterials have high sensitivity, specificity, and stability, making them potential candidates for use in environmental analysis, biosensors, food safety, and imaging techniques. First of all, a simple, eco-friendly, and low-cost electrochemical approach has been applied to the syntheses of carbon dots (C dots) from histidine hydrochloride in the absence or presence of halides (Cl, Br, and I) at various potentials up to 10 V. The halides play two important roles in determining the formation of C dots; controlling the reaction rate and surface states. Fourier transform infrared spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy results of I-C dots reveal the interactions of Cu2+ with the surface ligands (imidazole and histidine). The I-C dot probe in the presence of 0.8 mM I- is selective toward Cu2+ over the tested metal ions such as Hg2+ and Ag+. Practicality of this probe has been validated by the analyses of tap, lake, and sea water samples, with negligible matrix effects. In the second part, a one-pot, simple chemical oxidation approach has been applied to synthesize hydrophobic carbon dots (TO-C dots) at room temperature from triolein (TO) in concentrated sulfuric acid solution. Sodium copper chlorophyllin (SCC) quenches the fluorescence of TO-C dots by a photoinduced electron transfer process. Quantitation of SCC in flavored drinks shows percentage recovery (%R) vaues of 98–103% and relative standard deviation (RSD) values less than 6.5%. The hydrophobic TO-C dots can be simply converted into hydrophilic TO-C dots through hydrolysis in NaOH solution. The presence of sulfonyl groups on the hydrophilic TO-C dots enhances the coordination ability of the CDs toward Cu2+ ions, leading to fluorescence quenching which allows for the detection of Cu2+ ions. The assay has been validated with the analysis of spiked soil samples, with %R values of Cu concentration of 97.8–99.0% and RSDs below 2.0%. The surface tunable CD probes demonstrate their potential for the rapid screening of Cu2+ ions in environmental samples and SCC in foods. In the third part, m-Phenylenediamine carbon nanoparticles (mPA CNPs) were developed through one-pot hydrothermal reaction as a novel fluorescent probe (quantum yield = 10%) for pH and hypochlorite sensing. m-Phenylenediamine was chosen as the major component of CNPs for pH and hypochlorite responsiveness. Meanwhile, ascorbic acid with many oxygen-containing groups was introduced to generate favorable functionalities for improved water solubility and enhanced sensing response. The as-prepared mPA CNPs exhibited a linear fluorescence response over the pH ranges from pH 5.5 to 8.5 (R2 = 0.989), and over the concentration range of 0.125–1.25 μM for hypochlorite (R2 = 0.985). The mPA CNPs were further applied to the cell imaging. The mPA CNPs were also successfully used for cell imaging and sensitive detection of hypochlorite as well as pH changes in biological system. In the last part, a glutathione (GSH)-assisted approach in the presence of a polymer has been demonstrated for the preparation of stable and fluorescent gold nanoclusters (Au NCs). GSH acts as a reducing agent, while the polymer is used as a template to stabilize the as-formed Au NCs. The optimal pH value for the preparation of polymer-templated GSH-Au NCs is 11.0. With respect to the fluorescence intensity and stability, polydiallyldimethylammonium (PDDA) is more suitable than polystyrene sulfonate (PSS) for the preparation of Au NCs. The PDDA/GSH-Au NCs show sensitivity and selectivity for the quantitation of sulfide ions, with a linear detection range of 1–10 μM and a low detection limit (signal-to-noise ratio = 3) of 0.32 μM. The low-cost PDDA/GSH-Au NCs have been applied to the quantitation of sulfide ions in spring water samples with good accuracy and recovery.