| Organic small molecule fluorescent probes can trigger physical or chemical reactions by binding to specific analytes to generate corresponding fluorescent signals,so as to realize the selectively and sensitively visual detection of the analytes in the analysis environment.Such probes with excellent cell permeability and biocompatibility provide the possibility for non-invasive spatiotemporal monitoring of a given analyte in vivo and in vitro.Organic small molecule fluorescent probes can efficiently and quickly analyze analytes,and are extremely attractive tools in the fields of chemistry,biology,and medicine.In recent years,many fluorescen t probes based on small molecules have been developed to detect various cell components,diagnose related diseases,and develop drugs to treat diseases.Adenosine triphosphate is the most studied molecule in plants and animals because it has the function of generating and storing energy in living cells.In addition,it also participates in glycolysis,protein transport,Kreb cycle,ion channel regulation,activation signal cascade and other life activities.Abnormal lysosomal ATP concentration can cause lysosomal dysfunction,so the visualization of lysosomal ATP level is of great significance for exploring the biological processes related to lysosomal ATP.In this paper,the ATP fluorescent probe RP-ATP was constructed by acylation and amidation reaction.The probe uses rhodamine B and pyrene acid as the fluorophore,and the two are connected via the ATP-binding group diethylenetriamine through an amide bond.After ATP binds to the probe,it promotes the de-aggregation of pyrene and rhodamine B and the ring opening of the rhodamine B spirolactam ring.The solution turns from colorless to pink and the dual emission fluorescence is significantly enhanced.The probe identify ATP by colorimetric and fluorescence dual detection method.The response range of the probe to ATP is millimolar,matching the physiological concentration of ATP,the detection limit is as low as 1.27 ?M with high sensitivity,and it can recognize ATP in the lysosome in the acidic p H range.Cell experiments proved that the probe has low cytot oxicity,specifically targets lysosomes,and has the potential to monitor the dynamic changes of lysosomal ATP.G-quadruplex DNA is an irregular DNA secondary structure,which mainly exists in human telomeres and gene promoter regions,and participates in the regulation of DNA replication,genome stability,gene expression and telomere maintenance and other biological processes,moreover its folding and unfolding processes are closely related to the development of tumors,but the structure and function of G-quadruplex DNA are currently poorly understood Therefore,it is very important to develop a fast and efficient G-quadruplex DNA visualization detection method.In this paper,quinolinium dye fluorescent probes(QTH)and indolium dye fluorescent probes(IT H)are designed and synthesized.Both have similar photophysical properties in a viscous environment,but the probe ITH is not specific to G-quadruplex DNA.The probe QTH can selectively recognize G-quadruplex DNA among double-stranded DNA,singlestranded DNA,and G-quadruplex DNA.Its linear response range is 0-500 n M,and the detection limit is as low as 0.512 n M.The probe has high sensitivity,no cytotoxicity and can quickly(<5 s)recognize G-quadruplex DNA in the physiological p H range.Cell imaging experiments proved that the probe QTH has good resistance to photobleaching and is conducive to long-term stable imaging.Using this probe to observe the folding and unfolding process of G-quadruplex DNA is a powerful tool for intracellular G-quadruplex DNA imaging. |
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