鐵離子、次氯酸、硫醇螢光化學感測分子之設計與合成及於活體細胞之應用

Abstract

摘要 (一) 新型水溶性 Fe (III) 離子螢光化學感測分子及其細胞影像應用 以 rhodamine 為基底之新 Fe3+ 離子化學感測分子已成功設計與合成，相對於 Ag+、Al3+、Ca2+、Cd2+、Co2+、Cr3+、Cu2+、Fe2+、Hg2+、Mg2+、Mn2+、Ni2+、Pb2+ 及 Zn2+ 離子，化學感測分子 IS1 在水溶液中對 Fe3+ 離子具有絕佳的選擇性。化學感測分子 IS1 與 Fe3+ 離子結合而誘使 spirolactam 開環，產生波長 564 nm 的吸收峰及波長 588 nm 的放射峰，在 pH 值 6 至 7.5 之間變化效果最為顯著。由 Job plot 可知化學感測分子 IS1 與 Fe3+ 離子的結合比例為 1:1，而結合常數 Ka 為 6.9 x 103 M-1；藉由螢光顯微實驗，化學感測分子 IS1 可應用於觀測活體細胞內的 Fe3+ 離子。 (二) 二苯硒氧化反應機轉之螢光 Turn-on 次氯酸化學感測分子 以 BODIPY 為基底之螢光化學感測分子 HCSe 被成功發展應用於次氯酸的快速偵測。藉由次氯酸特定性氧化二苯硒官能基的作用機轉，可測定次氯酸的存在。透過共軛焦螢光顯微鏡亦展示此化學感測分子 HCSe 能有效觀測活體 RAW264.7 細胞中次氯酸的分布。 (三) 硫醇分子觸發 benzothiazolidine 環形成之螢光 Turn-on 化 學感測分子於 cysteine 及 homocysteine 的偵測 以 coumarin 為基底含雙硫鍵結構之新螢光化學感測分子 TP，可選擇性地被生物硫醇分子所切斷，導致強螢光放射的產生。此化學感測分子展示了對 Cys 及 Hcy 的優秀辨識能力而不受 GSH 及其他胺基酸的干擾。Cys 及 Hcys 觸發化學感測分子 TP 分子內 benzothiazolidine 環狀結構的形成，為促使螢光放射的重要特徵。

Abstract (1) New water-soluble highly selective fluorescent chemosensor for Fe (III) and its application to living cell imaging. A new rhodamine-based chemosensor IS1 exhibits excellent selectivity for Fe3+ ion over a wide range of tested metal ions Ag+, Al3+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Fe2+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ in an aqueous solution. The binding of Fe3+ to chemosensor IS1 produces an absorption band at 564 nm and an emission band at 588 nm because Fe3+-binding induces ring-opening of the spirolactam in IS1. The binding ratio of the IS1-Fe3+ complexes was determined to be 1:1 according to a Job plot. The maximum fluorescence enhancement caused by Fe3+ binding in IS1 occurred at a pH range of 6–7.5. The association constant (Ka) of Fe3+ binding in IS1 was 6.9 x 103M-1. The fluorescence microscopy experiments in this study demonstrated that chemosensor IS1 can be used as a fluorescent probe for detecting Fe3+ in living cells. (2) Hypochlorous acid turn-on fluorescent probe based on oxidation of diphenyl selenide. A BODIPY-based fluorescent probe, HCSe, has been successfully developed for the rapid detection of hypochlorous acid based on the specific HOCl-promoted oxidation of diphenyl selenide in response to the amount of HOCl. Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HCSe could be used as an effective fluorescent probe for detecting HOCl in living cells. (3) A fluorescence turn-on probe for cysteine and homocysteine based on thiol-triggered benzothiazolidine ring formation. A new coumarin-based probe TP, containing a disulfide moiety, can be selectively cleaved by biothiols which lead to strong fluorescence enhancement. The probe exhibits an excellent selectivity for cysteine (Cys) and homocysteine (Hcy) over glutathione (GSH)and other amino acids. Intramolecular benzothiazolidine ring formation triggered by Cys and Hcy is a key feature resulting in obvious fluorescence emission.