The Subcellular-targeted Red Fluorescent Dye:Release Of Reactive Oxygen Species,light-controlled Energy Transfer And Its Fluorescence Imaging

Reactive oxygen species participate in and maintain the normal life movement of human body.They play an important role in the treatment of related diseases and cancer.Light control technology has the advantages of simplity,minimal invasive,strong controllability and so on,which is widely used in the field of cancer treatment and diagnosis.On the other hand,as important subcellular organelles,mitochondria and lysosome are the places for oxidative stress,decomposition,digestion and apoptosis.Therefore,it is of great significance for human disease and cancer treatment to develop mitochondria-targeted or lysosome-targeted fluorescent molecules to detect and modulate the concentration of reactive oxygen species.Based on the above reasons,a series of mitochondria-targeted or lysosome-targeted photosensitizers were developed to modulate NO or ¹O₂ in the subcellular organelles and their biological effects were studied.In addition,a series of fluorescence resonance energy transfer-based ratiometric fluorescent probes were developed for the detection of HSO₃^-and their biological effects were studied.This paper would be discussed from the following eight chapters:Chapter 1:Firstly,the significance of reactive oxygen species in life activities and light control technology are summarized.Secondly,the design principles and research progresses of NO photosensitizer,¹O₂ photosensitizer and HSO₃^-fluorescent probe are summarized.Finally,the basis and research content of this paper are discussed.Chapter 2:A water-soluble photosensitizer Lyso-Rh-NO was synthesized based on rhodamine.With the N-nitroso group selected as the fluorescence quenching and light-controlled NO release unit,Lyso-Rh-NO could successfully control and monitor the release of NO through fluorescence signals and illumination time.The introduction of morpholine not only realized the water solubility of photosensitizer,but also promoted the lysosomal localization of Lyso-Rh-NO.Finally,Lyso-Rh-NO successfully released NO in zebrafishes.Chapter 3:Based on Lyso-Rh-NO,a 631 nm-emitting photosensitizer CA-NO was synthesized with the introduction of 4-aminoacetophenone to expand its?electronic structure.CA-NO could release NO in complex environment with high yield.However,the partial energy of CA-NO was released in the form of benzene rotation,which weakened the fluorescence signal.Hence,a photosensitizer CNA-NO with high fluorescence quantum yield was constructed by the introduction of the cyclohexane group to restrict the benzene rotation.The fluorescence quantum yield of CNA-NO increased from 0.79%to 20.31%after illumination,which was much higher than that of CA-NO(from 0.54%to 3.24%).Finally,CNA-NO released NO in living cells and zebrafishes successfully.Chapter 4:A red-emitting and water-soluble photosensitizer XAN-I was synthesized by the introduction of iodonaphthone into benzoxanthene.Compared with XAN-NH₂,the ¹O₂ yield of XAN-I increased from 3.86%to 8.24%.XAN-I had high phototoxicity and low dark toxicity.XAN-I could be effectively gathered in mitochondria to increase the unit volume of ¹O₂,which avoided the adverse effects of short half-life and effective distance of ¹O₂ and improved the PDT effect.Chapter 5:A water-soluble photosensitizer XAN-NO was synthesized for the combined therapy of NO and ¹O₂ based on N-nitroso group and benzoxanthene.XAN-NO released NO and formed XAN under the 465 nm irradiation while XAN generated ¹O₂ under the 610 nm irradiation.XAN-NO showed high phototoxicity with the 465 nm irradiation and XAN further enhanced the phototoxicity with the 610 nm irradiation,which indicated the superiority of the combined therapy of NO and ¹O₂.The successful release of NO and ¹O₂ from XAN-NO in living cells and zebrafishes indicated that the photosensitizer had good cell compatibility.Finally,XAN-NO was accumulated in mitochondria and induced the apoptosis of cancer cells under the synergistic effect of NO and ¹O₂.Chapter 6:A ratiometric fluorescent probe NPSCY was synthesized for the detection of Cys and PDT simultaneously.NPSCY used cyanine and naphthalimide as the main fluorophore and the thioether group as the linking group.NPSCY could distinguish the biothiols from three channels(Cys:733nm,435nm;Hcy:733nm,475nm)and displayed a low detection limit.In addition,NPSCY could produce ¹O₂quickly before and after reacted with biothiols.On the other hand,NPSCY could detect Cys in mitochondria and zebrafishes,which showed the good biocompatibility.NPSCY had high phototoxicity and low dark toxicity.Finally,cell migration analysis showed that NPSCY could inhibit the migration of cancer cells.Chapter 7:A FRET-based HSO₃^-fluorescent probe NPSI was synthesized by using piperazine to link naphthalimide and styrylindole.NPSI could distinguish HSO₃^-from biological thiols selectively in laboratory conditions and living cells effectively.However,due to the strong PET effect between naphthalimide and piperazine,the fluorescence of naphthalimide was limited.On the basis of NPSI,a new ratiometric fluorescent probe NPASI was synthesized by linking naphthalimide to the 1-position of indole with acetylpiperazine.NPASI weakened the PET effect in the naphthalimide and enhanced the fluorescent signal of naphthalimide successfully.NPASI showed fast response time and low detection limit.Finally,NPASI was aggregated in mitochondria and detected exogenous HSO₃^-successfully.Chapter 8:In summary,three water-soluble and photo-controlled NO releasing photosensitizers were synthesized and their biological properties were evaluated.Secondly,three mitochondria-targeted and photo-controlled ¹O₂ releasing photosensitizers were constructed and their cancer therapeutic properties were explored by the introduction of heavy atoms,NO and so on.Finally,two FRET-based ratiometric fluorescent probes for HSO₃^-were synthesized and their structure-activity relationships and biological applications were discussed.