Preparation Of Fluoroboron Compounds Based On AIE Properties And Their Applications In Bioimaging And Therapy

Traditional fluorescent materials often have disadvantages such as high concentration fluorescence quenching,poor stability and poor sensitivity,which limit their application in biological imaging.Compared with the traditional fluorescent materials,the aggregation-induced emission(AIE)fluorescent materials have the advantages of high aggregation fluorescence efficiency,strong photostability and good biocompatibility,and are widely used in the field of biological imaging and diagnosis and treatment.The stable fluoroboron complex formed by salicylaldimine is defined as Boranil.This structure has excellent fluorescence properties due to the strong push-pull electron interaction between the boron nitrogen single bond.Such compounds have excellent optical properties and easy synthesis characteristics,and have become a promising fluorescent material in the field of biomarkers and electroluminescent devices.Lipid droplet(LDs)is a dynamic organelle necessary for lipid storage and energy homeostasis regulation in cells,which plays a crucial role in many physiological processes(including lipid metabolism,signal transduction,protein degradation,etc.).Abnormal lipid storage in lipid droplets is also closely related to metabolic diseases.Therefore,the development of high-performance fluorescent probes specifically targeting lipid droplets is of great significance for the understanding of related biological processes and the early diagnosis of related diseases.In the first part of this paper,a series of Boranil compounds(DPFB-R)with AIE properties have been designed and synthesized by introducing phenyl substituents as molecular rotors on the basis of traditional Aggregation-caused Quenching(ACQ)Boranil compound DEFB.By introducing different R substituents,the fluorescence emission spectrum from 550nm to 601nm was regulated successfully.Due to its suitable lipopilicity and good biocompatibility,DPFB-R can specifically image lipid droplets in living cells.The DPFB-R has excellent lipid droplet imaging capabilities even under wash-free conditions.In addition,DPFB-R can also image the lipid tissue(yolk sac)of living zebrafish.In the second part of this paper,the compound MeO-H was synthesized by introducing methoxy group into the DPFB framework,and the conjugated groups of phenyl,styrene and phenylacetylene group were further inserted into the MeO-H molecule to design and synthesize three near-infrared Boranil molecules with A.IE characteristics(MeO-single,MeO-double,MeO-triple).Due to its suitable lipophilicity and good biocompatibility,this series of Boranil molecules can also specifically target lipid droplets in cells.In addition,under the irradiation of white light,this series of Boranil molecules can produce reactive oxygen species in different degrees,which made them have potential application value in the field of lipid droplet targeting photodynamic therapy.