Design,Preparation And Biological Applications Of Phosphorescent Iridium Complexes And Nanohybrid For Peroxynitrite Detection

Intracellular RONSS(reactive oxygen,nitrogen and sulfur species)provides broad implications in many physiological and pathological fields.Appropriate of RONSS is indispensable in some normal physiological processes.But the absence or excess of RONSS can lead to some physiological diseases.Among various RONSS,peroxynitrite is a potent biological oxidant.It has a short half-life in physiological conditions and is related to many diseases.Accurate peroxynitrite determination with superior selectivity and sensitivity is important for understanding biological roles of peroxynitrite in different health and disease tissues.Currently,the most materials for peroxynitrite detection are small-molecule fluorescent probes.It utilizes the changes in probe structure,electron cloud density,and luminescent properties after interaction with ONOO~-to comply peroxynitrite Detection.But most fluorescent probes have many shortages,such as poor water solubility,short fluorescence lifetime,and low quantum efficiency.Making it is impossible to accurately detect peroxynitrite in cells and living bodies.In this thesis,we synthesized a series of phosphorescent iridium complexes with phenylboronate as a recognition site for peroxynitrite.Then studied the photophysical properties of iridium complexes and application in detecting the intracellular peroxynitrite via fluorescence imaging and time-resolved photoluminescence imaging.The main contents are as follows:Firstly,we designed and synthesized four phosphorescent iridium complexes(Ir1,Ir2,Ir3 and Ir4).All the complexes contain phenylboronate as a recognition site for peroxynitrite.They would respond to peroxynitrite in generating phenolic group,leading to luminescence quenching and phosphorescence lifetime significantly reduced.Among them,complex Ir1 showing cyan phosphorescence with an emission maximum at 474 nm was selected as the responsive unit since it displayed the most remarkable“on-off”phosphorescent response for peroxynitrite.Confocal imaging and time-resolved techniques can be used to achieve specific detection of intracellular ONOO~-.Secondly,The nanoprobe consists of a specific peroxynitrite-responsive phosphorescent iridium(III)complex Ir1 and mesoporous silica nanoparticles(MSN-Ir3*)embedded with a nonreactive phosphorescent iridium(III)complex Ir3*-Si.Mesoporous silica hybrid nanomaterials(MSN-ONOO)have been prepared,the diameter of MSN-ONOO is about 50 nm and they can be well-dispersed in water.Studies have shown that it can be used to specifically detect ONOO~-in cells and zebrafish.In addition,we established a model of live rat inflammation and applied MSN-ONOO to detect the mouse inflammatory tissue production ONOO~-,the specific detection of ONOO~-in vivo was successfully achieved.