Design, Synthesis And Biological Application Of Fluorescent Probes Based On Self-destruct Structure

In the development of fluorescence imaging technology,fluorescent probes have the advantages of high sensitivity,high accuracy,strong selectivity,convenient and fast detection,etc.,and are mostly used in the field of life sciences.A large number of studies have explored various types of fluorescent probes and used them to detect biomarkers to achieve disease monitoring,but in fact only a few fluorescent probes can be commercialized and widely used in clinical medicine.The research of fluorescent probes Still in the stage of broadening the use of fluorescent probes and perfecting practical applications.Self-destruct chemistry enables the release of moiety structures in response to stimuli,often containing specific self-destruct spacers,which covalently link moiety-triggering molecules to substrates of interest,such as fluorophores,drugs,and other compounds.In this thesis,based on the self-destruct reaction,the fluorescent probe not only achieves the purpose of detection,but also adds other functions by modifying the self-destruct spacer.The research work carried out is as follows:（1）Hydrogen sulfide（H₂S）,as a signaling molecule involved in autophagy,is considered to be crucial in the occurrence and treatment of diseases.To elucidate the role of H₂S in disease processes,the dynamic visual detection of H₂S is urgently needed.We constructed a water-soluble near-infrared（emission wavelength of 695 nm）self-destructing fluorescent probe Cy SO₃N₃ for the detection of H₂S.It not only verified the ability of the probe to detect H₂S,but also improved the metabolic ability of the probe and reduced the toxicity of the probe.The probe can not only be used to detect H₂S in living cells and mice,but also detect changes in H₂S during inflammation and myocardial injury,and monitor cell self-repair processes by monitoring changes in H₂S.（2）In biological detection,the toxicity of the probe itself to the detected organism is often ignored,and it is urgent to reduce the toxicity of the probe under the premise of ensuring the detection performance.We constructed an analyte-compensated fluorescent probe（NP-SN₃）based on the structure of 1,8-naphthoimide for the detection of H₂S.Through the experimental results of Hep G2 cells,zebrafish embryos and juvenile images,it was found that there was no significant difference in imaging performance between the new probe and the traditional probe（NP-N₃）.After imaging activated HSC-T6 cells,the new probe showed lower detection-induced toxicity.During zebrafish embryo development and continuous dosing in rats,the new probe showed low embryonic mortality,high hatchability,and low malformation rates in zebrafish embryos.Stained tissue sections of rats also showed less pathological symptoms caused by the new probe.（3）In order to better understand and monitor the anticancer effect of H₂S in real time,a near-infrared fluorescent diagnostic probe YH-NO₂ based on the self-destruct reaction to release H₂S was designed and synthesized.After the probe is activated by the overexpressed nitroreductase in the tumor,it releases near-infrared fluorophore and H₂S simultaneously to realize the function of diagnosis and treatment of cancer.YH-NO₂ can not only distinguish nitroreductase activity under different degrees of hypoxia,but also identify normal cells and cancer cells by imaging.After verifying that YH-NO₂can stably release H₂S in cells,it was found that YH-NO₂ can not only selectively eliminate cancer cells,but also accurately identify and eliminate tumor tissues in vivo.These results indicate that the diagnosis and treatment mechanism of YH-NO₂ can not only monitor the anticancer effect of H₂S in vivo,but also play an important role in promoting the relationship between H₂S and cancer.（4）According to the self-destruct structure,a novel diagnostic probe Nap-NP-NSB combining fluorescent probe,H₂S and non-steroidal anti-inflammatory drug（NSAIDs）naproxen was developed,which can be associated with inflammation Moreover,the overexpressed ROS releases H₂S,naproxen and fluorophores at the same time after activation to achieve the purpose of diagnosis and treatment.Through fluorescence analysis of cell and tissue supernatants,Nap-NP-NSB enables the visual detection of synergy between H₂S and NSAIDs.In cells and in vivo,Nap-NP-NSB showed stronger anti-inflammatory effect and lower gastric mucosal damage side effects than naproxen.Combining fluorescent probes,H₂S,and NSAIDs demonstrates atom economy,provides a new way to study drug synergy,and expands the application prospects of fluorescent probes.