摘要 細菌檢測是許多疾病治療的基礎,傳統上關於細菌感染症的診斷,主要有賴於菌體培養增殖再進行分析鑑定,例如:酵素連結免疫吸附分析法(Enzyme-Linked Immunosorbent assay, ELISA)、聚合酶連鎖反應(Polymerse Chain Reaction, PCR)等技術,過程繁瑣且費時,若無法在黃金治療時間內檢測出致病菌並正確投藥,將危及患者生命。因此,發展能夠準確及快速檢驗致病菌的方法,是現今在檢測致病菌研究方面相當重要的課題。 本研究將金奈米粒子修飾上具有獨特拉曼光譜訊號的染料分子,在其表面包覆SiO2層,製備成奈米聚集團粒子(Nanoaggregate-Embedded Beads, NAEBs)。金屬奈米顆粒之間的熱點(hot spot)使NAEBs有強烈的SERS訊號,且外層受SiO2包覆能在不同環境下保持穩定性,因此可做為SERS標籤進行光譜之鑑定。目前已成功將3,3′-Diethylthiadicarbocyanine iodide (DTDCI)、Malachite green isothiocyanate (MGITC)、Tetramethylrhodamine-5-isothiocyanate (TRITC)、Crystal violet (CV)、X-rhodamine-5-(and-6)-isothiocyanate (5(6)-XRITC)等染料分子製備成具有特定分子拉曼光譜指紋之NAEBs標籤,進而檢測及應用。 在生化應用上,快速且可靠的偵測生化分子的濃度是必要的,例如:食品安全檢驗及藥物傳遞。其中,流式細胞術 (Flow Cytometry) 為一種廣泛使用的細胞分析技術,應用於臨床醫學及生化科學領域,此技術可快速偵測一顆接著一顆於液體中流動的顆粒或是細胞。本研究設計以聚二甲基矽氧烷 (Poly(dimethylsiloxane), PDMS) 製作的十字型微流體槽道,並利用氧電漿與玻璃片以鍵結方式封裝。藉由控制兩側邊鞘流流速可將樣本流聚焦,配合共軛焦拉曼顯微鏡在偵測區做分析,具有容易操作、低成本、高通量、快速檢測以及能夠專一辨識的優點。 本研究採用PDMS製作之微流體槽道,進行各式NAEBs拉曼標籤粒子之測試,並利用不同大小的聚苯乙烯 (Polystyrene, PS) 球,分別修飾上不同的抗原以模擬細菌;再將修飾上相對應辨識分子的NAEBs與其反應,控制兩側邊鞘流將PS球聚焦流過偵測區,並利用拉曼來偵測。實驗結果顯示,各式NAEBs拉曼標籤粒子皆有相對應的抗原與抗體吸附以及拉曼光譜鑑定。最後使用真實細菌樣品沙門氏菌及奈瑟氏菌進行檢測實驗,可偵測到利用專一性鍵結上的NAEBs-MGITC和NAEBs-DTDCI之拉曼光譜訊號,藉此驗證本研究確實能夠成功對真實細菌樣品進行聚焦辨識的功能。
Abstract Pathogen detection is the foundation of disease treatment. The current methods of pathogen detection, for instance, Enzyme-linked immunosorbent assay (ELISA) and Polymerse chain reaction (PCR), require lengthy procedures of cell culture, proliferation and detection. As a consequence, these methods tend to be tedious and time-consuming. Therefore, the development of an accurate and rapid method for analyzing pathogenic bacteria is highly desirable. In this work, we have developed a rapid, high-throughput, and specific bio-sensing platform for detecting particles or bacteria flowing one by one in a Poly(dimethylsiloxane) (PDMS) microfluidic chip using confocal Raman microscopy. We have demonstrated different Raman-labeled Nanoaggregate-embedded beads (NAEBs), each with a Raman reporter such as MGITC, TRITC, XRITC, DTDCI or CV. Furthermore, polystyrene (PS) microspheres of different sizes were used to mimic different bacteria and bio-functionalized for attachment of NAEBs. Results show that the flow cytometry-based system can identify the Surface-enhanced Raman scattering (SERS) signals of PS microspheres and bacteria when attached with Raman-labeled NAEBs.