Construction Of Novel Fluorescent Probes And The Application In Viscosity And GSH Detection

Cardiovascular disease and cancer are two global diseases with high morbidity and mortality.The former is abnormal hemostasis in blood vessels forming blood clots,leading to pulmonary embolism,myocardial infarction,stroke and other diseases.The latter is due to the abnormal change of genes in the body resulting in local malignant proliferation of tissue cells,thus inducing liver cancer,lung cancer and other diseases.Given that both diseases are characterized by low concentrations of biomarker molecules,wide regional distribution,and rapid metastasis,there is an urgent need to develop a comprehensive detection method combining high signal-to-noise ratio,in situ dynamics,and rapid deep tissue imaging.The current diagnostic methods include serological tests,imaging,and biopsy.Among them,serological detection suffers from poor sensitivity and specificity,imaging has low resolution and radiation side effects on pathological sites.Biopsy,as the gold standard for clinical diagnosis,is highly traumatic to patients,difficult to obtain repeated specimens,and prone to interference in diagnostic results.None of the above methods could achieve highly sensitive and in situ dynamic detection of disease markers.Therefore,it is urgent to develop more ideal disease diagnostic tools to achieve highly selective and sensitive detection of disease markers and accurate in situ tracing of lesion sites.Fluorescence imaging is an ideal imaging detection method with high spatial and temporal resolution,high sensitivity,deep penetration of tissue and millisecond imaging time.At present,many fluorescent probes have been developed in domestic and international studies for imaging cardiovascular disease and cancer,respectively,but there is still a lack of effective fluorescent probes to achieve in situ,high-sensitivity detection of disease markers.Thus,the design of contrast agents for accurate real-time detection of disease markers provides sufficient guarantees for early visualization of thrombotic plaques or cancerous sites.More importantly,studies have shown that viscosity and glutathione(GSH),which are overexpressed in thrombosis and cancer,can serve as ideal disease biomarkers.Therefore,there is an urgent need to develop specific activated fluorescence probes for precise imaging analysis of viscosity and GSH-related disease markers,which is expected to open up a new way for early detection and tracer of thrombus and cancer.To solve the above problems,two novel fluorescence probes were constructed in this thesis,which respectively realized the viscosity-specific activation of near infrared(NIR)thrombus fluorescence imaging and GSH activated tumor fluorescence imaging.The details are as follows:1.A viscosity-activated NIR fluorescent probe(TIR-V)targeting thrombus was designed and synthesized for highly selective and sensitive in situ thrombus lighting.The fluorescence probe was composed of three parts: fibrin-specific binding pentapeptide CREKA as thrombus targeting group,using a flexible conjugate bond to cyclohexene linked benzindoles as viscosity response part and cyanine dye with large π-conjugated system as NIR fluorophore.TIR-V exhibited distinct advantages including precise thrombus targeting capability,fluorescence response to viscosity specificity,NIR fluorescence emission and good biocompatibility.More importantly,TIR-V is capable of high signal-to-noise,in situ imaging to detect thrombus and precisely navigation guided thrombus resection by ideal brightness.In conclusion,this study systematically demonstrated NIR imaging analysis and accurate navigation of the thrombus site in living mice by TIR-V.Based on a synergistic strategy of thrombus targeting and viscosity lighting,TIR-V has great potential to improve the accuracy of thrombus detection and treatment.2.A viscosity fluorescence response fluorescence probe(PG-V)activated by GSH was designed and synthesized for detection imaging and resection of tumors.In the probe structure,the disulfide bond was used as the recognition reaction group of GSH,the single and double bond conjugated part of benzoindole was used as the viscosity response group,and merocyanine dye was used as the fluorophore.The probe PG-V first broke the disulfide bond by response to the high expression of GSH in cancer cells,and then,with the increase of viscosity,the intramolecular rotation was limited,resulting in a further enhancement of fluorescence intensity.The probe could effectively respond the change of viscosity through GSH activation,and showed a good linear relationship in the detection.In addition,the probe has good photostability in the physiological range and strong anti-interference against active molecules such as reactive oxygen species and reactive nitrogen species.The probe can not only be used to further study the correlation between cellular and in vivo viscosity changes,but also its fluorescence characteristics will provide the basis for the study of navigating cancer sites by cascade reaction imaging.