以三磷酸腺苷及酸鹼值調控銀奈米團簇邏輯閘

Abstract

本論文主要利用寡核苷酸 (oligonucleotide, OND) 為模版合成銀奈米團簇 (OND–Ag nanoclusters, OND–Ag NCs)，經由調控三磷酸腺苷 (Adenosine 5’-Triphosphate, ATP) 及酸鹼值，將 OND–Ag NCs 之螢光特性變化應用於建造不同邏輯閘。同時也應用 OND–Ag NCs 偵測水溶液中的 ATP 濃度。在不同酸鹼值 (pH 3.0–11.0) 下，OND–Ag NCs 之螢光強度及波長會隨之變化。在 pH 3.0 及 11.0 時，ATP 濃度變化會對 OND–Ag NCs 之螢光特性有顯著的影響。在 pH 3.0 時，隨著 ATP 濃度由 10 μM 增加至 50 μM，OND–Ag NCs 之螢光放光波長會從 525 nm 紅位移至 585 nm。而在 pH 11.0 時，OND–Ag NCs 於波長 510 nm 之螢光強度則會隨著 ATP 濃度增加而增強。因此，藉由調控氫離子 (H+) 及 ATP 濃度作為輸入訊號，可由 OND–Ag NCs 在 pH 3.0 時之螢光強度 (IF510) 及比值 (IF510/IF585) 作為輸出訊號而發展出反及閘 (NAND) 和反或閘 (NOR) 兩種邏輯閘。而以氫氧根離子 (OH−) 及 ATP 濃度作為輸入訊號時，利用 OND–Ag NCs 在 pH 11.0 時之螢光強度 (IF510) 作為輸出訊號便能開發出包含邏輯閘 (IMP)。此外，利用 OND–Ag NCs 之螢光強度比值 (IF525/IF585) 會隨著 ATP 的濃度增加而下降之現象，其 ATP 的偵測極限 (limit of detection，LOD) 為33 nM，線性範圍落在 100 nM 到 10 μM之間。此偵測系統也能進一步應用於分析細胞萃取液 (cell lysate) 樣品中之 ATP 濃度。

Oligonucleotide templated Ag nanoclusters (OND–Ag NCs) have been prepared and used for construction of NAND, NOR, and IMPLICATION (IMP) logic gates, as well as for the detection of adenosine-5’ triphosphate (ATP). The OND–Ag NCs are prepared from AgNO3 using an OND with a sequence of 5’-TAACCCCTAACCCCT-3’ as a template and NaBH4 as a reducing agent. The fluorescence intensity and emission wavelength of OND–Ag NCs are dependent on the pH value and ATP concentrations. At pH 3.0 and 11.0, ATP shows greater effects on fluorescence of the OND–Ag NCs. Upon increasing ATP concentration from 10 to 50 μM, the emission wavelength of OND–Ag NCs at pH 3.0 shifts from 525 to 585 nm. At pH 11.0, the fluorescence intensity (510 nm) increases upon increasing ATP concentration. Through control of two inputs—[H+] and ATP concentrations—, and use of fluorescence intensity (IF510) and ratio (IF510/IF585) of OND–Ag NCs at pH 3.0 as outputs, NAND and NOR logic gates have been developed, respectively. Using [OH−] and ATP concentrations as inputs and IF510 of OND–Ag NCs at pH 11.0 as an output, an IMP gate has been demonstrated. The OND–Ag NCs provide linearity of IF525/IF585 ratios against ATP concentration over the range of 0.1–10 μM, which allow determination of ATP concentrations in cell lysate samples.