從2007年的瘦肉精事件、2008年的三聚氰胺毒奶粉事件、2011年的塑化劑事件，到近年來層出不窮的農藥超標事件，食品安全問題已經成為台灣的重大議題之一。雖然目前已經發展出許多高精準度的分析技術如層析法、質譜法和免疫蛋白測定法等，然而，精密的檢驗方法同時也存在著許多弊端：除了本身的檢測流程複雜之外，需要較長的分析時間，費用更是高昂，這些缺點大大限制了此檢測技術在日常上的應用。因此要如何找出既具有高靈敏性、成本也較低廉的快速檢測方法，成為目前甚被關注的重要議題之一。
在眾多檢測分析方法中，拉曼散射光譜是一種強而有力的分析技術，他能提供分子結構上的資訊並應用於快速篩选以及分子檢測上。然而，拉曼訊號的強度並不高，複雜的環境背景值會減弱甚至無法辨別目標待測物的拉曼訊號。因此，發展出一個簡單的檢測樣品前處理技術搭配高靈敏的拉曼散射光譜成了近年來研究的關注議題。在本論文中，我們優化了一種低成本且製程簡單的多功能表面增強拉曼檢測晶片，此晶片由先前的研究團隊提出，其同時擁有超薄層液相層析法以及表面增強拉曼效應的功能，藉由複雜混合樣品中個別分子對於固相晶片和液相溶液間親和力的差異，能夠將目標待測物自混合物中分離出來，進而大幅提升其信躁比。
此多功能三維表面增強拉曼檢測晶片主要利用化學濕式刻蝕法形成的矽奈米線和銀奈米顆粒裝飾而成，其後以SiNWs@Ag來稱呼此基板。SiNWs@Ag基板可以在銀奈米顆粒之間透過表面電漿子共振的方式在特定區域形成電磁訊號增強的熱點(hotspot)，以此來增強目標待測物的拉曼訊號。此外，矽奈米線提供高表面積，使其具備了分離混合物的功能。和先前的研究相比，我們進一步利用氫氧化鉀的蝕刻拓寬矽奈米線的間距，使得銀奈米顆粒能夠貼附於奈米線之間及更深的區域，形成三維表面增強拉曼的結構，達到更好的表面增強拉曼效應。
在此研究當中，我們首先確立奈米線的各項製造參數，包括奈米線生成速率及氫氧化鉀的蝕刻速率。接下來，製備出包括奈米線長度和奈米線間距等不同幾何形狀的基板，並利用不同顏色的染料證明其具備層析功能，以及探討基板幾何形狀對表面增強拉曼效應的影響。因此，藉由調整SERS基板幾何結構和金屬奈米顆粒之間的距離，我們可以調整表面增強拉曼效應的強度，使得晶片效能達到最佳化。本實驗結果顯示，和原始的基板相比，3微米長度和448奈米寬間距的最佳化奈米線陣列結構能夠有效將拉曼訊號提升近102倍。並且透過將加保利農藥從果汁中分離檢驗的實驗，證實了此晶片能應用於實際的檢測，為生醫感測等領域提供了更好更實際的應用選擇。

Nowadays, food-additive crisis has become a serious safety issue in Taiwan. Several disconcerting crises including Melamine additive in milk, Ractopamine additive in food animals, and Malachite green additive in farmed fish have caused highly concerned in recent years. However, a simple and convenient method is lacked to identify these toxic chemical composites. Although the laboratory analytic detection techniques including high-performance liquid chromatography(HPLC), liquid chromatography/mass spectroscopy (LC/MS) and immune-assays can obtain a robust analytic result, it accompanies several insufficiencies such as high-cost, complexity, and long detection and analysis time, which limit its application in our daily usage. Therefore, developing a low cost and high-performance analytic platform for biochemical applications is a must to solve abovementioned issues.
In this research, we optimized a low cost, easily fabricated SERS/UTLC multifunctional chip, which is proposed from the previous research team. Such chip implements the functions of both surface-enhanced Raman scattering (SERS) and ultra-thin liquid chromatography (UTLC) to separate the target analyte from the mixture and also detected by the Raman spectroscopy with high signal/noise ratio at the same time.
The optimized 3D-SERS/UTLC multifunctional chip composed of silicon nanowires decorated with silver nanoparticles is fabricated by a simple chemical wet etching process, thereafter depicted as SiNWs@Ag. Silver nanoparticles provide abundant electromagnetic hotspots among silver nanoparticles to enhance Raman signals of a target through localized surface Plasmon resonance (LSPR). Furthermore, the SiNWs offer a high surface to volume ratio to present the function of liquid chromatography. Comparing to the previous work, the interspace of SiNWs are further enlarged though KOH etching process, therefore allow silver nanoparticles to deposit not only on top of the nanowires but also between the nanowires, forming a 3-dimension SERS structure. Consequently, the Raman signal of the targets can be dramatically further enhanced in the Raman spectrum.
Follow the pervious study, our work is to discuss the influence of the SiNWs@Ag’s geometry to the Raman signal enhancement and further improve the performance of the origin SERS/UTLC multifunctional chip. In this study, we first determined the fabrication parameters of the SiNWs@Ag chip. Different geometries of substrates including the lengths of the SiNWs and interspaces between the SiNWs are fabricated and examined utilizing dyes to establish the influence of the substrate geometries to the Raman enhancement. According to the result, the optimized 3D-UTLC/SERS chip with 3um length and 448nm interspace of the SiNWs reveals a nearly 100 times larger Raman signal than the origin substrate. Moreover, the mixture of two dyes are separated to prove the functionality of UTLC. Finally, the detection of pesticide Carbaryl from a juice mixture is demonstrated for practical applications. As a result, by integrating a simple fabrication process and low-cost 3D-SERS/UTLC multifunctional chip, a high biochemical sensing chip for rapid screening is achieved in this work.

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