Two near-infrared highly sensitive cyanine fluorescent probes for pH monitoring  

作　　者：Jing-Ru Hou Di Jin Bo Chen Lei-Lei Si Yue-Hua Jin Li-Gong Chen Xi-Long Yan Bo-Wei Wang Yang Li 

机构地区：[1]School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China [2]Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300350,China [3]Tianjin Bohai Fine Chemical Co.,Ltd.,Tianjin 300300,China [4]Tianjin Engineering Research Center of Functional Fine Chemicals,Tianjin 300350,China

出　　处：《Chinese Chemical Letters》2017年第8期1681-1687,共7页中国化学快报（英文版）

基　　金：financial support from the National Natural Science Foundation of China(No.21576194)

摘　　要：Two near-infrared（NIR） p H-activated heptamethine indocyanine probes with quaternary ammonium unit were designed and synthesized. The absorption and emission titrations indicate that cationic structure improves the cyanine dye＇s aqueous solubility and these two probes exhibit highly sensitive response to p H in acid condition. Their fluorescence intensities both gradually increase about 25-fold from p H 7.60 to 3.00 with p Ka values of 4.72 and 4.45 respectively, which are suitable for studying acidic organelles in living cells. Moreover, their fluorescence intensities are linearly proportional to p H values in the range of 5.50–4.00. These results are probably attributed to the protonation of the indole nitrogen atoms, which are verified by 1H NMR spectra. Furthermore, these two probes can achieve real-time imaging of cellular p H and detection of p H in situ in living He La cells due to their excellent properties,including good reversibility, desirable photostability, high selectivity, low cytotoxicity and remarkable membrane permeability.Two near-infrared（NIR） p H-activated heptamethine indocyanine probes with quaternary ammonium unit were designed and synthesized. The absorption and emission titrations indicate that cationic structure improves the cyanine dye＇s aqueous solubility and these two probes exhibit highly sensitive response to p H in acid condition. Their fluorescence intensities both gradually increase about 25-fold from p H 7.60 to 3.00 with p Ka values of 4.72 and 4.45 respectively, which are suitable for studying acidic organelles in living cells. Moreover, their fluorescence intensities are linearly proportional to p H values in the range of 5.50–4.00. These results are probably attributed to the protonation of the indole nitrogen atoms, which are verified by 1H NMR spectra. Furthermore, these two probes can achieve real-time imaging of cellular p H and detection of p H in situ in living He La cells due to their excellent properties,including good reversibility, desirable photostability, high selectivity, low cytotoxicity and remarkable membrane permeability.

关 键 词：pH fluorescent probe Near-infrared Indocyanine Quaternary ammonium Biological imaging 

分 类 号：O657.3[理学—分析化学]