Construction And Application Of Novel Fluorescent Probes Based On Naphthalimide Dyes

1,8-Naphthimide dyes had a large rigid conjugated plane.They are characterized by easily modification.After introducing an electron-donating group at the 4-position or 3-position,they form pash-pull electronic system,which emit strong yellow-green fluorescence.Due to their relatively good fluorescence properties,naphthalimide dyes have been widely used in the fluorescent dye industry.Naphthalimide dyes generally have good biocompatibility,so the research and development of such dyes as fluorescent probes are also a hot spot in current research.With deeper understanding of the fluorescent mechanism,many naphthalimide-based fluorescent probes have been developed.The detected substances involve various metal cations,non-metal anions,small biological molecules,and active substances in the body(active oxygen species,active sulfur species,active nitrogen species,etc.),as well as biological macromolecules and so on.With the development of physiopathology and cytology,there were investigations indicated that changes in diseases will affect the internal environment of organelles,and cause abnormal changes in the content of related substances.Therefore,developing fluorescent probes with targeted functions can be located related organelles,identify related substances,and accurately monitoring abnormal changes of related substances,thus providing help for inestigating of disease pathology or treatment of related diseases.Here,in the thesis,three naphthalimide-based fluorescent probes based were designed and synthesized,two of them had specified targeting ability.The first fluorescent probe was a pH fluorescent probes which could detect of pH changes in the nucleus and lysosomes,and the second one is CO fluorescent probes targeting mitochondria.The third is a CO fluorescent probe targeting cancer cells.(1)The cellular internal environment is generally sensitive to pH.Lysosomes are distributed with a variety of enzymes which were necessary for life activities.These enzymes are more sensitive to pH.There are enzymes that control genetic information in the nucleus,its requirements for pH are even more demanding.In order to detect of pH changes of these two subcellular organelles more accurately,we designed and synthesized a pH probe NpH-1,which had rapid and reversible response to pH.The p Ka value of the probe was5.96.The imaging results show that the probe is mainly distributed in the lysosome and the nucleus,which can measure pH changes in these two sub-organelles,and provides a powerful help for further understanding cellular activities.(2)Endogenous CO is an important reactive oxygen species in the body.With the deepening of studies,it has been discovered that CO had significant roles in living cells.A large amount of endogenous CO has also been discovered in subcellular components such as mitochondria.However,it was still not clear the role of CO in mitochondria.Thus in,we designed and synthesized a mitochondria-targeting CO fluorescent probes N-PDs,which have specific recognition capabilities for CO and high selectivity and low cytotoxicity.The detection limit of the probe was 0.07 n M.It has many advantages in cell imaging.The positive charge introduced in the probe provides help for the probe to pass the mitochondrial membrane and provided a powerful tools to study endogenous CO.(3)Compared with normal cells,cancer cells are particularly active cells,and they are also the place where produced a large amount of endogenous CO However,the role CO played in cancer cells was still not clear.Therefore,in order to explore the role of CO in cancer cells in the process of cancer cell proliferation,we took advantage of the overexpression of cancer cells and used biotin as a target of the cancer cell,designed and synthesized a CO fluorescent probe N-SWs.The probe specifically recognized CO under more than 50 selective interferences,and had high sensitivity,with a detection limit as low as0.147 μM.It has low toxicity to 3T3 and 4T1 cells,and is good for entering cancer cells without killing them.It could provide theoretical basis and preliminary help for investigating the importance of CO in cancer cells.