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  • 學位論文

生物分子感測: 鋅離子螢光感測以及釋 放一氧化氮分子之螢光二硫二鐵亞硝基 錯合物

Approaches toward Biomolecule Detections: Zinc Ion Fluorescence Sensing and Nitric Oxide Releasing Fluorescent Roussin's Red Ester

指導教授 : 洪政雄 陶雨台

摘要


為了調整金屬芳烴作用力,我們合成出了在meso苯環間位上擁有特殊官能基 (-H,-COOMe,-NO2) 之不同的benziporphodimethene,並在其tripyrrin環中心配位不同的d10金屬離子。根據核磁共振研究,金屬芳烴作用力與環內中心金屬之酸性成正相關:當meso苯環間位官能基拉電子能力較強時便會造成較強的金屬芳烴作用力。雖然我們所合成的benziporphodimethene金屬錯合物之晶體結構均呈現syn構形,然而在meso苯環間位由-COOMe所取代之鋅離子錯合物的晶體結構中,卻是由約90%之syn構形與約10%之anti構形所共同組成。這些金屬錯合物其syn和anti構形間的交換乃是由於軸配位基之解離與重新結合。理論計算顯示anti構形可經由溶劑分子與軸配位基上之氯離子間之氫鍵作用力而被穩定。 除了上述的研究,benziporphodimethene亦被發現可作為優秀的鋅離子感測染料。此些染料在與鋅離子結合後會於672 nm產生螢光。其偵測極限為48nM。以事先培養於鋅離子之乳癌細胞進行實驗,共聚焦顯微鏡影像顯示水溶性benziporphodimethene均勻的呈現在整個細胞中。 水溶性的benziporphodimethene被發現會於水溶液中逐漸進行水分子加成反應而變成一在環內氮原子氫化以及meso碳原子上羥化之化合物。此新生成物與原本之水溶性benziporphodimethene於溶液中呈現平衡狀態,平衡常數於298K時為0.84,於348K時為0.16。新生成之化合物對鋅離子有很低的結合力,且其對鋅離子不會有螢光反應。然而,透過簡易地於溶液中先後加入酸液以及鹼液,我們可將新生成物轉換成原本之水溶性benziporphodimethene. 為了提高染料與鋅離子的結合力,我們亦合成出tripyrrinone鋅離子螢光感測分子。它與鋅離子的結合力相對於benziporphodimethene增強了約30倍。對於細胞內鋅離子之偵測,tripyrrinone只能偵測到細胞質內的鋅離子,無法進入細胞核。我們發現tripyrrinone系列化合物的螢光量子產率高度的取決於meso取代基之動態運動。當對meso位置為苯環取代之tripyrrinone做激發時,此兩苯環之動態旋轉消耗了處於激態之分子的能量,導致螢光量子產率只有4%。而當我們將meso位置取代基換成立體障礙較大之mesityl或2,6-dichlorophenyl時,螢光量子產率便大幅增加至接近90%。此外,tripyrrinone鋅離子錯合物在非配位溶劑中會聚合成雙偶體或四偶體並導致螢光嚴重降低。而在有配位能力之溶劑環境中則會形成單分子,同時螢光也會大幅增強。 我們亦設計了14-benzoyl-tripyrrinone鈷錯合物,想要用以進行一氧化氮的偵測。藉由紅外線光譜、氫離子核磁共振圖譜,以及紫外光-可見光吸收光譜,我們已確認了一氧化氮確實配位於中心鈷離子上,而錯合物卻未因此而產生螢光。我們另外合成了3,4-diamino-N-(2-morpholin-4-yl-ethyl)-benzamide分子,此化合物含有溶脢體螢光標靶性質,並且算是鄰二氨基芳基環系列的ㄧ種,可用以感測一氧化氮於空氣下之衍生物,N2O3。此感測劑在四氫呋喃溶液中於387nm的位置顯現出強烈螢光。而此螢光在與一氧化氮於空氣下反應後便會消失。同樣的反應在水溶液中進行時,螢光則是從443nm藍移至376nm。 我們亦合成了二硫二鐵亞硝基錯合物作為一氧化氮提供分子。其具有溶脢體標靶性質並以naphthalimide為其基底。此分子可藉由藍光或綠光之照射而釋放一氧化氮分子。當一氧化氮分子由雙鐵中心釋放後,進一步的光照射將促使掛載著naphthalimide的硫醇鹽氧化而形成偶合之二硫化物並且產生螢光。因此,我們可將此螢光的產生作為一氧化氮已經釋放之判斷依據。

並列摘要


Benziporphodimethenes with different functional groups (-H, -COOMe, and -NO2) on the para position of the meso-phenyl rings were inserted with a d10 metal ion in order to tune the metal-arene interaction. According to the 1H NMR study, the strength of the metal-arene interaction can be correlated to the acidity of the central metal ion: an increased electron withdrawing ability resulted in stronger metal-arene interaction. Although all of the reported solid state crystal structures of the metal complexes show a syn conformation, a crystal containing mixture of syn- (about 90%) and anti-conformation (about 10%) was obtained from the zinc complex of meso-methylbenzoate substituted benziporphodimethene. It is confirmed that the syn-anti conformational exchange for these metal complexes goes through the axial ligand dissociation and re-association. Theoretical calculations revealed that the anti conformation can be stabilized by intermolecular hydrogen bonding interactions between the axial chloride and solvent molecules. These benziporphodimethenes can specifically turn on fluorescence at 672 nm upon coordination with Zn2+. The detection limit is 48 nM. In vitro zinc ion sensing in Zn2+ enriched Hela cells was performed using a water soluble benziporphodimethene. Confocal images demonstrated that the water soluble benziporphodimethene stains the whole cell including the cytoplasm and nucleus. The water soluble benziporphodimethene was found gradually to undergo a water addition reaction to transform into an amino nitrogen protonated and meso-carbon hydroxylated species in aqueous solution. This newly formed species and the original benziporphodimethene are in equilibrium in solution with equilibrium constants of 0.84 at 298 K and 0.16 at 348K. The newly formed species was found showing low affinity and having no fluorescence in contact with the zinc ion. Dehydration back to the original benziporphodimethene can be readily achieved by subsequent treatment with acid and base. Tripyrrinone was synthesized to provide a Zn2+ sensor with higher binding affinity and a 30-fold enhancement on the binding affinity toward Zn2+ than benziporphodimethene has been detected. For the cellular zinc ion sensing, tripyrrinones only showed fluorescence turn-on in the cytoplasm without penetrating into the nucleus. Fluorescence quantum yield of the tripyrrinone dyes were found strongly dependent on the dynamic motion of the meso-substituent. The dynamic rotation of the meso-phenyl rings seriously quenches the fluorescence quantum yield to 4%; while replacing the phenyl rings with bulky mesityl or 2,6-dichlorophenyl rings, the fluorescence quantum yields increase to about 90%. Besides, in a non-coordinating solvent, the tripyrrinone zinc complexes assemble to form a dimmer or a tetramer structure with weak fluorescence. While in coordinating solvents, the monomer geometry exhibits much stronger fluorescence. The 14-benzoyl-tripyrrinone cobalt complex is designed for nitric oxide (NO) sensing. The coordination of NO to the cobalt center has been proved by the IR, 1H NMR, and UV-Vis spectroscopy; however, there was no fluorescence turn-on observed. Another lysosome targeting NO sensing dye, 3,4-diamino-N-(2-morpholin-4-yl-ethyl)-benzamide, was developed based on the sensing of the diaminoaryl to the NO derivative, N2O3. This probe shows strong emission at 387 nm in THF, and the fluorescence will be quenched upon the reaction of the dye with NO in aerobic condition. While in aqueous solution, a blue shift of fluorescence from 443 to 376 nm is observed from the same reaction. We have also developed a lysosome-targeting-naphthalimide-based Roussin’s red ester as a NO donor. The NO can be released upon irradiation with blue or green light. After NO releasing from the diiron center, further irradiation will promote the oxidation of the naphthalimide-thiolate to form disulfide dimmer and turn on the fluorescence. The fluorescence turn-on phenomenon is proved to be the signal for the releasing of NO.

並列關鍵字

Benziporphyrin Zinc ion Sensor Lysosome NO donor Roussin's Red Ester

參考文獻


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