Near-infrared Fluorescent Probes Based On BODIPY And Xanthene Dyes: Design Synthesis And Fluorescence Imaging Applications

The application of fluorescent probes in the biological field plays an important role,and some important substances in living organisms(Reactive Oxygen Species,Enzymes,etc.)are closely related to physiological and pathological processes.Therefore,it is significant to develop fluorescence detection methods for these important substances.Because most of the emission of conventional fluorescent probes is in the short wavelength region,their application is greatly limited.However,the characteristics of near-infrared fluorescent probes with strong penetration and low bioautofluorescence have promoted the development of fluorescent probes in vivo fluorescence imaging.Based on this,two near-infrared fluorescent probes for detecting biomolecules were synthesized by using BODIPY fluorophore and xanthene fluorophore,and a novel near-infrared fluorescent dye for xanthene fluorophore was designed and synthesized.The main research work is summarized as follows:First,a BODIPY near infrared fluorescent probe(BDP)was designed and synthesized for detection of carboxyleesterase(CEs),and the acetyl group of the probe BDP was used as CEs recognition group.The probe BDP showed good selectivity for CEs.The fluorescence intensity was linear for CEs concentration in the range of 0.3-2.0 U/m L,and the detection limit was 0.066U/m L.The response mechanism of fluorescent probe BDP to CEs was investigated by high resolution mass spectrometry(HRMS)and density functional theory(DFT)calculations.More importantly,the probe BDP aggregated in the mitochondria of the cells and was successfully used for endogenous CES fluorescence imaging of cells and Daphnia Magna.Second,a near-infrared fluorescent probe(CL-1)for xanthene with rapid response and high selectivity to hypochlorous acid(ClO~-)was developed.The dimethylthiocarbamyl group of probe CL-1 is used as the ClO~-recognition group.The absorption peak of probe CL-1 shifted from 550nm to 670 nm in response to ClO~-.The fluorescence intensity at 730 nm showed a good linear in the range of 0-40?M for ClO~-.The detection limit was 1.81?M,and the detection limit can be reduced to 0.146?M at p H=8.In addition,the results of optical stability experiments show that the fluorescent probe CL-1 has excellent optical stability.The response mechanism of probe CL-1to ClO~-was investigated by high resolution mass spectrometry(HRMS).More importantly,the probe CL-1 was successfully applied to the fluorescence imaging of endogenous and exogenous hypochlorous acid in RAW 264.7 cells.Third,a novel near-infrared fluorescent anthracene dye(TM-1)was designed and synthesized by two routes.The absorption and emission of the fluorescent dye TM-1 are more redshifted than that of the reported fluorescent dye(RM),reaching the near-infrared region,and has excellent light stability.In addition,we proved that the fluorescent dye TM-1 has low cytotoxicity and good membrane permeability through cytotoxicity experiments and cell fluorescence imaging experiments.The research results provide a preliminary basis for the subsequent fluorescence detection and fluorescence imaging of this dye.