Study On Large Stokes-shifted Dye And Simultaneous Imaging Of Lysosomal And Mitochondrial NO Fluorescent Probes

Near-infrared fluorescent dyes have the advantages of low biological background,strong penetrability to biological samples,and small light damage,and have shown good application prospects in biology,medicine and clinical diagnosis.Increasing the Stockes Shift of the dye causes the emission wavelength of the dye to be red-shifted to the near-infrared region(600-900 nm),which is conducive to the fluorescence imaging of tissues and living bodies.Moreover,the small Stokes shift results in large spectral overlap,and its backscatter phenomenon is obvious,which results in significant self-absorption phenomenon and low signal-to-noise ratio of biological samples.Therefore,increasing the Stokes shift can improve the accuracy and sensitivity of fluorescent dye imaging.Nitric oxide(NO)is an important biogas messenger molecule,mainly produced in mitochondria.It is involved in the regulation of mitochondrial respiration and is closely related to many functions of lysosomes.Its abnormal expression will lead to mitochondrial and lysosome functions.Loss,causing a series of diseases.In view of this,the development of fluorescent probes capable of imaging NO in mitochondria and lysosomes is of great significance for understanding their physiological and pathological effects.Based on the above two points,the main research contents of this paper are as follows:(1)Four fluorescent dye molecules,BT1,BT2,BT3,and BT4,were designed and synthesized by using benzothiazole iodide salt as a fluorophore and introducing benzyloxy groups in its ortho-,meta-,and para-positions.Among them,the emission wavelengths of BT2 dye molecules substituted by ortho and meta positions are red-shifted to 609 nm,and the maximum Stokes shift can reach 196 nm.And its absorption peak and emission peak have almost no spectral overlap,small self-absorption effect,and good signal-to-noise ratio.This method of increasing the Stokes displacement has a clever effect,has low cost,simple synthesis and convenient operation.(2)An o-phenylenediamine-functionalized rhodamine deoxyamide-type NO fluorescent probe Mito-NO was designed and synthesized.The probe can specifically target mitochondria and can selectively and rapidly fluorescein the mitochondria endogenously.NO.Based on this probe and combined with a lysosomal-targeted silodane deoxylactam-type NO fluorescent probe Lyso-NO previously reported by our research group,this paper has realized mitochondria and lysozyme from two visible and near-infrared fluorescence channels.Simultaneous fluorescence sensing of in vivo-derived NO provides an excellent imaging tool for exploring the physiological and pathological functions of NO.