表面電漿共振 (surface plasmon resonance, SPR) 生物感測器因為具有不需標記、高靈敏度、專一性與即時檢測等優點,因此被大量使用在生物檢測上。而光纖式表面電漿共振生物感測器則因為其微小化的外型、材料價格低廉與微小的感測區使得可應用於小體積樣本的檢測,其應用範圍越來越廣泛。 本研究使用光纖式表面電漿共振感測器來進行生物小分子檢測之研究,使用表面電漿共振的檢測系統,需在感測表面上做良好的表面修飾,以提升檢測靈敏度與變異度。本研究以mercapto-undecanoic acid (MUA)與不同碳鏈長度物質β-mercaptoethanol (2-MEOH) 與6-mercapto-1-hexanol (6-MHOH) 依不同比例混合作為自我聚集單層 (self-assembled monolayer, SAM) 沉積在光纖式SPR晶片的感測表面,並固定biotin-albumin bovine serum (biotin-BSA),作為一個小分子的檢測平台。 結果顯示,在矽晶片的試驗中,6-MHOH為SAM層或是使用混合SAM層皆可讓biotin-BSA的固定量較單一的MUA SAM層增加,但在本系統的光纖SPR感測時,過多的biotin-BSA固定量可能造成SPR訊號的不穩定,相較之下,MUA的biotin-BSA固定量不是最多,但在光纖感測系統的穩定度卻是最大。 而在光纖的訊號放大試驗上,選擇一般研究中常用的酵素沉澱法和奈米金法作為訊號放大的試驗方法,結果顯示,以3,3’-diaminobenzidine tetrahydrochloride (DAB) 作為基質的酵素沉澱放大方法較適用於本系統中。因此MUA為SAM層及DAB沉澱訊號放大此兩條件為本光纖式SPR系統之最適條件。
Surface plasmon resonance (SPR) biosensor has several advantages such as lable-free, high sensitivity, specificity and real-time detection, so it has been used for a large number of biomolecular detection. The fiber-optic SPR biosensor is low cost and has small size due to its small sensing area, it makes the sensor ideal for studying small volumes of samples. The applications are more and more than before. In this study, we used the fiber-optic SPR sensor to determine the small biomolecules. Using SPR detect system needs to make a good modification layer on the sensing surface to improve the detecting sensitivity and stability. Mercapto-undecanoic acid (MUA) mixed molecules with different length of carbon chains, β-mercaptoethanol (2-MEOH) and 6-mercapto-1-hexanol (6-MHOH), in different ratio to deposit as self-assembled monolayer (SAM) on the sensing surface, and then biotin-albumin bovine serum (biotin-BSA) was immobilized on SAM surface of fiber-optic SPR as a detection platform for small molecular analytes. The results show that SAM layers by single 6-MHOH or MUA mixed with 6-MHOH could immobilize more biotin-BSA than one by single MUA in silicon wafer system. In fiber-optic SPR sensing system, however, excess biotin-BSA could cause unstable in the SPR signal. In the contrast, the immobilized biotin-BSA was less for MUA SAM layer, but the stability in fiber SPR sensing system is the best. In the test for SPR signal amplification, we select enzyme precipitation method and nanogold method that common used in other studies. And then, the enzyme precipitation method that use 3,3’-diaminobenzidine tetrahydrochloride (DAB) as substrate is better in this fiber-optic SPR system. Therefore, using MUA as the SAM layer and amplifying the signal by DAB precipitation are the better conditions to the fiber-optic SPR system.