DNA金屬奈米團簇之合成及應用

Abstract

本篇論文包含兩個部份分別是使用毛細管電泳技術結合雷射誘導螢光偵測系統，分離不同片段DNA合成之發光金屬奈米團(nanoclusters, NCs)，及應用發光銅銀奈米團簇(Cu/Ag NCs)以消光機制測定水溶液中之過氧化氫(hydrogen peroxide, H2O2)和葡萄糖(glucose)。首先，我們在三種不同序列及長度(24、32、40 bases)之單股DNA存在下，合成DNA-銀奈米團簇，再利用毛細管電泳來分離DNA-銀奈米團簇，在含陰離子界面活性劑(12 mM sodium dodecyl sulfate, SDS)的線性聚合物(poly(ethy1ene oxide), Mw: 8.0E+6 Da, 0.75%）溶液中，於電滲透流(electroosmotic flow, EOF)存在的條件下進行毛細管電泳分離，可在6分鐘內成功分離三種不同的DNA-銀奈米團簇，因SDS可改變金屬團簇之表面電荷分布，及減少DNA-銀奈米團簇及PEO吸附於毛細管壁，故可顯著提升分離的效果。 我們亦利用H2O2可使DNA-Cu/Ag NCs發光強度下降之現象，來開發偵測H2O2和葡萄糖之感測器。在溫度25oC，反應60分鐘條件下，DNA-Cu/Ag NCs 偵測H2O2之偵測極限(limit of detection, LOD)為0.5 μM，其線性範圍為1至100 μM。利用葡萄糖與葡萄糖氧化酶(Glucose oxidase, GOx)反應產生H2O2，故DNA-Cu/Ag NCs感測器亦可用來偵測葡萄糖，其LOD為15 μM。最後將此感測器進一步應用偵測血液中的血糖濃度為4.58 (±0.32) mM，符合理論值的範圍。

There are two parts to this thesis: one is to separate different DNA-Ag nanoclusters (NCs) by combining capillary electrophoresis technique with laser-induced fluorescence detection system (CE-LIF); another is to apply fluorescent Cu/Ag NCs to measure H2O2 and glucose concentration in the aqueous solution by quenching effect. At first, forming DNA-Ag NCs from three kinds of single DNA fragments with different sequences and lengths (24, 32, 40 bases), which are then subsequently separated by using capillary electrophoresis. Under optimal conditions, we were able to separate the above mentioned DNA-Ag NCs in six minutes in the presence of EOF. The fact that SDS increases separation efficiency greatly might be attributed to a change in surface electron distribution of DNA-Ag NCs and decreasing DNA-Ag NCs and PEO attachment to capillary wall. We also developed a simple fluorescent sensor approach for the detection of H2O2 and glucose using a DNA-Cu/Ag NCs probe. Under the optimal condition, the DNA-Cu/Ag NCs probe was highly sensitive toward H2O2 ( LOD~0.5 μM ) and the linear range was found to be between 1 to 100 μM. Moreover, the production of H2O2 in the glucose solution was owing to the presence of glucose oxidase (GOx). DNA-Cu/Ag NCs probe can be used to detect glucose concentration with an LOD of 15 μM. Finally, we used it to analyze blood glucose as 4.58 (± 0.32) mM.