基于ESIPT机理的近红外硫醇探针及其生物成像研究  

ESIPT-based near-infrared probe for thiols and its biological imaging

作　　者：任海仙[1,2] 张婷 REN Hai-xian;ZHANG Ting(Department of Chemistry,Xinzhou Teachers University,Xinzhou 034000,China;Institute of Molecular Science,Shanxi University,Taiyuan 030006,China)

机构地区：[1]忻州师范学院化学系,山西忻州034000 [2]山西大学分子科学研究所,山西太原030006

出　　处：《分子科学学报》2022年第2期174-180,共7页Journal of Molecular Science

基　　金：2020年度省高等学校科技创新资助项目(2020L0541)。

摘　　要：本文利用激发态分子内质子转移(ESIPT)过程可产生长波长酮式发射的特点,以HBT(2-(2’-羟基苯基)苯并噻唑)为骨架,2,4-二硝基苯磺酸基作为硫醇位点掩盖酚羟基,与丙二腈缩异佛尔酮通过共轭双键相连,构建了近红外硫醇探针SYN.该探针实现了近红外区对硫醇的定量检测,并在细胞水平上对硫醇进行了成像研究.Thiols including cysteine(Cys),homocysteine(Hcy)and glutathione(GSH),played important roles in cell growth and metabolism.Abnormal concentrations of Cys would cause the change of iron homeostasis and the damage of mitochondrial function.The content of Hcy in plasma was about 15μmol·L^(-1),and its abnormally high concentration would lead to thrombosis.Both Cys and Hcy could be metabolized to produce GSH in vivo.GSH,as an antioxidant and free radical scavenger,was involved in maintaining cellular redox homeostasis.In this work,we used benzothiazole and isophorone to prepare the near-infrared ESIPT(excitedstate intramolecular proton transfer)-based fluorescent dye SY.2,4-dinitrobenzenesulfonyl as the reaction site for thiols was employed to mask the phenolic hydroxyl group of SY,to yield probe SYN.When 1 mmol·L^(-1)thiols were added to the solution of probe SYN,the sulfonate group was cleaved then SY was released due to the strong nucleophilic ability of the thiol group.SY was unstable in the excited state,and the phenolic hydroxyl proton was easily and rapidly transferred to the electron-rich nitrogen atom of the adjacent thiazole ring to form a keto excited state,namely,SY underwent an excited state intramolecular proton transfer process.Probe SYN exhibited distinct emission at 470 nm,and when 1 mmol·L^(-1)thiols(Cys,Hcy or GSH)were added,the near-infrared emission was observed.Different thiols caused different emission intensity at 686 nm.The signal caused by GSH was weaker than that of Cys and Hcy.It was indicated that three thiols could release hydroxyl groups through the nucleophilic substitution reaction,enabling the ESIPT process to occur.The emission at 470 nm was decreased along with an increase of the intensity at 686 nm.The reaction rates of three thiols with the probe were significantly different(Cys>Hcy>GSH),which was directly related to their pKa.The response of probe SYN to Cys reached equilibrium within 20 min,while the response to Hcy and GSH reached equilibrium within 40 and 120 min,respective

关 键 词：ESIPT 硫醇 荧光探针 近红外 

分 类 号：O654[理学—分析化学]