Development Of Dual Wavelength Fluorescence Probe For Live Cell Imaging And Reversible Photo-responsive Solid Sensors

Fluorescent probes with dual-wavelength emission show color changes in different cellular environments,which should be the ideal choice for dynamic study of live cell processes.Therefore,studying dual-color fluorescent probes is of great significance in the development of live cell imaging methods.Photo-responsiveness is direct and fast with high spatiotemporal resolution.Dual-wavelength reversible photo-responsive solid materials are not only ideal in optical information storage,but also display unique advantages in the usage of sensing,anti-counterfeiting,and confidentiality.This dissertation developed a class of fluorescent probes for dual-color imaging and dynamic imaging studies of living cell processes based on the structure design and chemical synthesis of dual-colored fluorophore.Meanwhile,this dissertation studied the molecular structure design and sensing system construction for dual-wavelength reversible light response and developed two types of reversible solid sensors with dual wavelength photoresponsiveness.For the development of probes,we synthesized TPNPDA-Cn dual-colored fluorescent probes combined with aggregation-induced emission(AIE)and twisted intramolecular charge transfer(TICT)for live cell imaging.According to molecular structural design,a push-pull AIE fluorophore with electron donor and accepter was applied to make the probe emit red or yellow fluorescence with high photostability when at different spatial conformation.Modification of hydrophilic and hydrophobic groups at the luminescent structure gives the amphiphilicity to the probe.The localization of the probe in subcellular organelles of living cells is regulated by adjusting the length of the hydrophobic alkyl chains.Among them,TPNPDA-C12 was capable of imaging cell membrane(red fluorescence)and mitochondria(yellow fluorescence)simultaneously and had been successfully applied to dynamically image changes in cell membrane and mitochondria during apoptosis induced by different factors.TPNPDA-C15 displayed excellent cell membrane specificity and enabled long-term dual-color dynamic imaging of membrane lipid order changes.The imaging of TPNPDA-C15 was applied for the first time to analyze and study the competing processes of phosphatidylserine translocation and cell shrinkage throughout apoptosis on a temporal scale.And the significant differences in lipid order changes during ferroptosis and apoptosis was also studied.For the development and study of solid sensors,photochromic nanofiber meshes were prepared based on electrospinning using photochromic dye spiropyran(SP)doped polycaprolactone(PCL).The color of the fiber meshes was reversibly switched between white and purple upon irradiation with ultraviolet(UV)and green light,respectively.Through the design of the template and the regulation of the dye content,a variety of patterned wearable fibrous sensors were successfully prepared for real-time display of the UV index in the environment.The reversible photoactivated AIE properties of triphenylmethanol(TPOH)and some derivatives were investigated.And it was found that on the silica surface,upon irradiation with 254 nm or 365 nm UV,respectively,a reversible switch between the blue fluorescent and nonfluorescent states of TPOH was achieved.The process was most likely that the positive triphenyl carbon ion generated by light irradiation was stabilized on the solid surface and emitted fluorescence.This property was successfully used to prepare rewritable photopatterning solid materials.