【摘要】：卟啉是一種性能優(yōu)良的近紅外熒光發(fā)色團,以其為母體設計合成的熒光探針,在近紅外光區(qū)進行檢測時可以有效減小復雜生物樣品中背景熒光的干擾,提高檢測的準確性和分辨率。目前基于卟啉結構設計合成的熒光探針以陽離子探針居多,而中性分子及陰離子探針鮮少報道。中性分子和陰離子在探針識別過程中的相互作用較弱,且大多數(shù)的中性分子及陰離子探針是通過與分析物之間發(fā)生化學反應導致體系熒光強度變化來達到識別目的。因此,設計合成卟啉類中性分子和陰離子探針較陽離子探針更具有挑戰(zhàn)性。同時,研究表明,簡單地改變熒光團中取代基的位置可以很好地提高熒光探針分子的選擇性。選擇性的改變探針會更好地避免生物體及環(huán)境中干擾離子的影響,使探針對目標化合物的檢測更為精準。本文以卟啉為母體,根據(jù)PET機理設計合成了高位阻可識別硫離子、苯硫酚及巰基氨基酸的熒光探針。因為這些探針受光激發(fā)后發(fā)生PET過程,并且擁有高的位阻,所以探針本身的空白熒光很弱。而當加入目標化合物后,分子內PET過程被抑制,體系熒光得到明顯的提高。主要內容如下:首先,我們以不同取代位置的單羥基苯基卟啉為母體,2,4-二硝基苯磺酰氯為識別部分合成得到了兩種硫離子熒光探針M1、M2,利用核磁、質譜等分析手段進行了結構表征。優(yōu)化探針M1、M2的測試條件后,得知兩個探針對硫離子均有較好的響應。但將兩個探針的選擇性比較之后發(fā)現(xiàn):探針M1較M2更具有選擇的專一性。經(jīng)分析,探針M1的位阻較高,在一定程度上抑制了巰基化合物的進攻,而促使體積較小的硫離子進入發(fā)生親核反應。因此,增大探針的空間位阻有利于探針選擇性的提高。其中,探針M1的線性范圍為3×10-6 mol/L~9×10-6 mol/L,檢出限為40 nM,探針M2的檢出限為62nM,線性范圍為1×10-6 mol/L~8×10-6 mol/L。其次,基于上述結論,將2-單羥基卟啉和NBD-Cl為原料合成了一種高位阻的苯硫酚熒光探針M3。該探針在加入苯硫酚前后熒光發(fā)生變化,并且在1×10-6 mol/L~7×10-6mol/L的濃度范圍內呈現(xiàn)良好的線性關系,檢出限為54 nM。最后,我們在2-單氨基卟啉接入馬來酰亞胺基團,得到了一種熒光增強型的可識別巰基氨基酸的探針M4。當加入巰基氨基酸(GSH、Cys、Hcy)后,與探針之間發(fā)生環(huán)合反應,抑制了PET過程,體系的熒光強度得到增強。同時,還檢測了6種非巰基氨基酸,結果發(fā)現(xiàn)體系的熒光光譜并沒有發(fā)生變化,表明探針M4可以用來區(qū)分巰基氨基酸和非巰基氨基酸。
[Abstract]:Porphyrin is a kind of near infrared fluorescence chromophore with excellent properties. The fluorescence probe designed and synthesized with it as the parent can effectively reduce the interference of background fluorescence in complex biological samples when it is detected in the near infrared region. Improve the accuracy and resolution of detection. At present, cationic probes are the most common fluorescent probes based on porphyrin structure design, while neutral molecules and anion probes are rarely reported. The interaction between neutral molecules and anions in the process of probe recognition is weak, and most neutral molecules and anion probes achieve the recognition purpose by chemical reaction with analytes to cause the change of fluorescence intensity of the system. Therefore, it is more challenging to design and synthesize porphyrin neutral molecules and anion probes than cationic probes. At the same time, it is shown that simply changing the position of the substituted group in the fluorescent cluster can improve the selectivity of the fluorescent probe molecule. Selective change of probe will better avoid the influence of interference ions in organism and environment, and make the detection of target compounds more accurate. In this paper, a fluorescence probe with high resistance to recognize sulfur ions, phlorophenol and sulfhydryl amino acids was designed and synthesized according to the mechanism of PET. Because the PET process occurs after these probes are excited by light and has high steric resistance, the blank fluorescence of the probes itself is very weak. When the target compound was added, the intramolecular PET process was suppressed and the fluorescence of the system was improved obviously. The main contents are as follows: first, we synthesized two kinds of sulfur ion fluorescence probes M1, M2by using monohydroxyphenyl porphyrins with different substitution positions as parent and 2, 4-dinitrobenzenesulfonyl chloride as recognition part. The structure was characterized by mass spectrometry and other analytical methods. After optimizing the test conditions of probe M _ 1 and M _ 2, it was found that the two probes had good responses to sulfur ions. However, after comparing the selectivity of the two probes, it is found that probe M1 is more selective and specific than M2. The results show that the steric hindrance of probe M1 is high, which suppresses the attack of sulfhydryl compounds to a certain extent, and causes the smaller sulfur ions to enter the nucleophilic reaction. Therefore, increasing the steric hindrance of the probe is beneficial to the improvement of the selectivity of the probe. The linear range of probe M1 is 3 脳 10 鈮，

本文編號：2480763