Synthesis And Bioimaging Of Aryl P/Se Substituted BODIPY Fluorescent Probes At Meso Position

Reactive oxygen species or reactive sulfur small molecules are not only involved in maintaining intracellular redox balance,but also closely related to a variety of physiological and pathological processes,such as cardiovascular diseases and nervous system diseases.The development of new probes capable of detecting these bioactive small molecules is of great significance for in-depth analysis of the pathological mechanism of disease occurrence and development and related clinical detection.Fluorescent probes have the advantages of good selectivity,high sensitivity,fast response,and have great advantages in real-time and in-situ detection of redox small molecules.It is still very urgent to develop fluorescent probes with high selectivity and specificity for the detection of redox small molecules.The molecular structure of fluorescent probes has an important influence on their recognition performance.BODIPY dyes have excellent photophysical properties,and can effectively regulate the absorption and emission spectra of BODIPY dyes through different substituents at meso-position,which are widely used as fluorescent probes.At present,N,O,S-substituted meso-BODIPYs have shown good optical properties and are used to construct fluorescent probes,but there are few reports on P,Se-substituted BODIPY derivatives.Therefore,starting from the molecular structure design,this paper introduced electron-rich P/Se at the meso site to construct a new type of BODIPY probe substituted by heteroatoms at the meso site,and explored its reaction mechanism for detecting redox small molecules and its application in biological imaging.The work mainly included two aspects:1.Synthesis and bioimaging of meso-aryl P substituted BODIPY fluorescent probes.We designed and synthesized novel meso-P substituted BODIPY derivatives,BP(8-diphenylphosphine-BDDIPY)and TMBP(1,3,5,7-tetramethyl-8-diphenylphosphine-BDDIPY).Based on the photoinduced electron transfer(PET)effect,BP initially had no fluorescence,after reacted with Cl O~-,the newly generated P=O bond blocked the PET effect and generated fluorescence emission.BP had high selectivity,high sensitivity(LOD=1.9 n M)and fast response time(<15 S)for Cl O~-,and has been successfully applied to the detection of endogenous and exogenous Cl O~-in living RAW 264.7 cells and imaging of inflammation in mice.TMBP only showed a colorimetric response to Cl O~-without any fluorescent signal.It is speculated that the possible mechanism was that there was a large steric hindrance between the methyl groups at C1/C7 site and the substituents at the meso position,which destroyed the planar structure of BODIPY core excited state.Compared with BP,TMBP cannot be applied to the detection of redox small molecules.2.Synthesis and bioimaging of meso-aryl Se substituted BODIPY fluorescent probes.We designed and synthesized two novel meso-Se substituted BODIPY fluorescent probes,TMBSe(1,3,5,7-tetramethyl-8-phenylselenol-BODIPY)and BSe(8-phenylselenol-BODIPY).The probe BSe could realize the differential detection of GSH and Cys/Hcy,but could not realize the differential detection of Cys and Hcy.The emission wavelength of probe TMBSe after reaction with GSH/Hcy was 550 nm,while intramolecular rearrangement occurred after the reaction with Cys,resulting in an obvious blue shift,and the emission wavelength was at 500 nm.Due to the steric hindrance effect of methyl at C1and C7 site of TMBSe,Hcy could not continue molecular rearrangement reaction,and the differential detection of Cys and GSH/Hcy was realized.Confocal imaging experiments showed that the probe TMBSe could detect exogenous Cys/Hcy in living RAW 264.7 cells by dual-channel imaging.