Chemosensors Based On Thermally Activated Delayed Fluorescent Dyes And Their Applications

Following traditional fluorescent materials and phosphorescent materials,thermally activated delayed fluorescence(TADF)materials have become the third generation of organic light-emitting materials due to their efficient reverse intersystem crossing(RISC)and intersystem crossing(ISC)efficiency.It has been widely studied in the fields of time-resolved imaging and photodynamic therapy.Compared with traditional fluorescent materials,TADF materials have long-life luminescence in the order of microseconds.Compared with phosphorescent materials,it has the advantages of low production cost and low biological toxicity due to the absence of precious metals.Compared with traditional probes,fluorescent probes designed with TADF as the precursor have a long lifetime of microseconds,which is beneficial to eliminate short-lived background fluorescence.It can be applied to photodynamic therapy and designed as a molecule with integrated functions of diagnosis and treatment.The TADF dye DCF-MPYM,which has been published by our research group,was chosen to design new probes by derivatization.Using levulinic acid as the recognition site,a sulfite fluorescent probe with microsecond-level long-life fluorescence was designed.Using the azo group as the recognition site,a fluorescent probe that recognizes the over-expressed azo reductase in the hypoxic environment of tumor cells was designed and applied to photodynamic therapy.