摘要
本論文中利用粒徑為2 nm且表面修飾11-巰基十一酸(11-Mercaptoundecanoic acid，11-MUA)的金奈米點(gold nanodots，Au NDs)，簡稱11-巰基十一酸–金奈米點(11-MUA–Au NDs)，偵測水溶液中的過氧化氫(hydrogen peroxide，H2O2)及葡萄糖(glucose)。11-MUA–Au NDs具有放光的特性，並且有大的Stokes shift(145 nm)、長的放光生命期(τ1與τ2分別為36和231 ns)，以及良好的量子產率(quantum yields，QYs = 3.1 %)等光學性質，適合用於生物樣品分析，不受背景基質的干擾。 強氧化劑H2O2與11-MUA–Au NDs混合反應後，氧化11-MUA，改變Au NDs的表面特性，使得11-MUA–Au NDs螢光減弱，且螢光下降的幅度隨著H2O2的濃度增加而上升，在最佳化的反應條件(溫度65℃，反應30分鐘)，H2O2的偵測極限(limit of detection，LOD)為30 nM，其線性範圍落在100 nM到1.0 mM。與H2O2反應後的Au NDs再添加進11-MUA，可使其螢光值回復，藉由調控所添加11-MUA的濃度，可以重複使用此一偵測系統。 測定溶液中葡萄糖濃度時，混合葡萄糖溶液與葡萄糖氧化酶(glucose oxidase，GOx)，使其反應產生H2O2，再加入11-MUA–Au NDs感測器至反應完的溶液中，即可進行葡萄糖濃度偵測。與血糖中其他醣類(果糖、乳糖和麥芽糖)相比，對葡萄糖具有較高的選擇性(大於30倍)，且偵測極限達到1.0 μM，可應用在血清樣品中葡萄糖濃度測定，並有著操作簡便、便宜、再現性高且精準的優點。
並列摘要
This thesis focuses on a novel gold nanodot (Au ND)-based sensor for the determination of hydrogen peroxide (H2O2) in aqueous solution and, vicariously, of glucose in serum with high sensitivity and selectivity. The fluorescence intensity of 11-mercaptoundecanoic acid-bound Au NDs (11-MUA–Au NDs) was quenched in the presence of H2O2 as a result of the oxidation of 11-MUA mediated by H2O2. The decrease in fluorescence intensity was proportional to the logarithm of the concentration of H2O2 over the range of 100 nM–1.0 mM, with a limit of detection (LOD) of 30 nM at a signal-to-noise ratio of 3. After each assay, the addition of 11-MUA restored the fluorescence; thus, the sensor system was readily regenerated. To optimize the sensitivity of the detector toward glucose, a two-step analysis assay had been developed: (i) glucose was reacted with glucose oxidase and (ii) the produced H2O2 was detected using the 11-MUA-Au ND nanosensor. This sensing system provided high selectivity (30-fold or more) for glucose over fructose, lactose, and maltose, with an LOD of 1.0 μM. Because the 11-MUA-Au ND nanosensor has a long Stokes shift (145 nm), matrix interference was minimal, allowing simple sample preparation and providing excellent linearity. This research validated the practicality of this sensing system by analyzing glucose in serum. This approach provides the practical benefits of simplicity, low cost, reproducibility, and precision.