| The luminescence signal of a conventional fluorescent probe is mainly based on changes in emission intensity or wavelength,which is easily affected by some factors,such as sample concentration and excitation power.They can reduce the accuracy of detection.However,the emergence of long-lived phosphorescent metal complexes provides a new strategy for solving the difficulties and challenges encountered in luminescence imaging,and has become a new research hotspot in the field of biosensing and bioimaging.It has the following characteristics:（1）good photostability,which makes it possible to monitor the changes of the microenvironment in the cell in real time without being affected by long-term illumination;（2）long phosphorescence lifetime,which can eliminate the interference of short-lived background fluorescence through time-resolved luminescence imaging technology to improve the signal-to-noise ratio and accuracy of the detection;（3）large Stokes shift,which greatly reduces the possible self-absorption and self-quenching phenomenon;（4）triplet excited state,which can make complex used as a photosensitizer to produce singlet oxygen（1O2）and other reactive oxygen species under light irradiation for photodynamic therapy.This thesis focuses on the application of phosphorescent metal complexes for ion detection and photodynamic therapy.The main research contents are lised as follows:1. Design and photophysical properties of aggregation-induced phosphorescent iridium（III）complex for fluoride detectionFluoride,as the smallest halogen anion with highest charge density,not only plays an important role in maintaining dental health,but also can be used to treat osteoporosis and other diseases.However,the excessive intake of fluoride can cause the problems of stomach,kidney and other organs.It can even lead to poisoning biological tissues.So the detection of fluoride is particularly important.Herein,we designed a phosphorescent probe Ir-AF by introducing tert-butyldiphenylsilane（TBDPS）in the C^N ligands of the iridium（III）complex,which is used for the detection of fluoride in aqueous solutions and living cells.The probe has the characteristics of aggregation-induced phosphorescence emission（AIPE）,which solves the problems such as the quenching of luminescence（ACQ）caused by aggregation in conventional fluorescent probes.The strong affinity between fluoride and Si is used to break the Si-O bond in the probe structure,and the sensitive detection of fluoride in the aqueous solution is achieved through the change of emission intensity and lifetime.In addition,the probe Ir-AF has the advantages of long phosphorescence lifetime,excellent biocompatibility and good photostability.Through confocal imaging and time-resolved luminescence imaging technology,the interference of short-lived background fluorescence is avoided and the accurate detection of fluoride in living cells is realized.2. Phosphorescent ruthenium（II）complex for apoptosis detection and photodynamic therapyIn addition to being used as probes for sensing,phosphorescent metal complexes can also be used as photosensitizers to generate reactive oxygen species under specific light irradiation and induce cancer cell apoptosis.However,in the process of PDT-induced apoptosis,the traditional method used to detect apoptosis is to use two fluorescent reagents,such as annexin V and nuclear stain,to label cells.Although quantitative data are provided,it cannot achieve real-time in situ monitoring of apoptosis process.To solve this issue,we designed a phosphorescent ruthenium（II）complex Ru1,as the photosensitizer.When studying the photodynamic therapy effect,it was found that after the compound Ru1 was irradiated with a xenon lamp,a large amount of reactive oxygen species was generated in the cells to induce apoptosis,and at the same time,the luminescence of complex was quenched Therefore,the complex Ru1 can act as a self-reporting photodynamic therapy system and realize the real-time in situ monitoring of cell apoptosis. |
