The Construction Of AIE Probes Based On Tricyanfuran As Electron Acceptor And Their Applications In Biological Theranostics

Theranostics combining of diagnosis and therapy can effectively improve the treatment precision and reduce side effects.Fluorescent probes have significant advantages in terms of high spatiotemporal resolution,excellent sensitivity,real time and in situ imaging ability.To date,many theranostic agents have been developed by combination of fluorophores and therapeutics.However,traditional fluorophores suffer from aggregation-caused quenching(ACQ),which seriously restrict their applications in theranostics.In contrary with ACQ fluorophores,the aggregation-induced emission(AIE)fluorogens are featured with high emission efficiency in the aggregate state,which can overcome the drawbacks of traditional ACQ fluorophores.Moreover,the AIE fluorogens in the aggregate state have excellent photostability,which facilitate the long-term monitoring.Based on these unique advantages,AIE probes have been widely used in biosensing and bioimaging.Although it is highly desirable for development of theranostics to improve the treatment efficiency and precision,most of current AIE theranostic systems require the decoration of stimulus-responsive linkers and easily lead to generation of toxic by-products.To tackle this challenge,herein,two AIE probes of DBATCF and TPATCF with D-?-A characteristics were constructed based on tricyanofuran(TCF)as the electron acceptor,vinyl as the conjugated linker and triphenylamine or triphenylamine-thiophene as the electron donor.These AIE probes can not only be used for lipid droplets(LDs)-specific imaging,but also can react with S^2-to form the corresponding AIEgen-S conjugates and be used for wound exudate(water)-responsive release of hydrogen sulfide(H₂S)to promote wound healing.The detailed research is discussed as following:(1)The abnormal accumulation of LDs is closely related with obesity,diabetes and cancer.Therefore,the LDs-specific imaging with high signal-to-noise ratio is highly desirable for study of the related diseases.In the second chapter,two D-?-A type AIE probes,DBATCF and TPATCF,were constructed by using tricyanofuran(TCF)as the electron acceptor,vinyl as the conjugated linker and triphenylamine or triphenylamine-thiophene as the electron donor.Based on the restriction of intramolecular motion(RIM)and intramolecular charge transfer(ICT)mechanisms,these AIE probes are featured with near-infrared(NIR)emission and high photostability,which can be used for rapid and wash-free imaging of LDs even under two-photo irradiation.They can also be used for revealing of the relationship between LDs accumulation and pathological conditions.(2)Skin is the first protective barrier of the human body and it is extremely vulnerable to traumatic injuries,burns and other injuries.Hydrogen sulfide(H₂S)can promote the skin wound healing by reducing inflammation and increasing angiogenesis.In the third chapter,we found that TPATCF can undergo quantitative Michael addition reaction with S^2-in dimethyl sulfoxide to form the TPATCF-S conjugate,which can act as a wound exudate(water)-responsive theranostic probe to promote wound healing.Taking full-thickness skin defect of rats as a model,H₂S was quickly released by TPATCF-S once contacting wound exudate,which significantly accelerated the process of wound healing.Meanwhile,the release process of H₂S can be in situ monitored.This theranostic probe has excellent biocompatibility because it does not generate any toxic by-product during the release of H₂S.