Development Of Fluorescent Probe For Hydroxyl Radical And Light Control System

Up-conversion luminescence,that is,light emission shorter than the excitation wavelength,due to the clear emission band,low autofluorescence interference,high chemical stability,high light stability,high signal-to-noise ratio,short response time and other advantages,in the past few decades It is widely used in various fields,especially in the fields of chemical sensing and drug-loaded therapy.Among them,the up-conversion process is common in two-photon fluorescent probes and up-conversion nanomaterials.Two-photon fluorescence uses near-infrared excitation,the penetration depth is higher than that of single-photon fluorescence,and the effective excitation volume is smaller than single-photon excitation,and the resolution is higher.Lanthanide-doped up-conversion nanoparticles（UCNP）emit high-energy photons after being excited by near-infrared（NIR）light,and are ideal nanocarriers for guiding drug delivery.Based on the above advantages,my master’s thesis mainly carried out the following two aspects of work:In the first work,we constructed a ratio-type two-photon fluorescent probe and used it for the quantitative analysis and imaging of hydroxyl radicals（·OH）in hypoxia model mouse neurons and zebrafish.The triphenylphosphine group in the probe serves as a mitochondrial targeting group,while the coumarin group（CM）and naphthimide group（NPM）serve as the donor and acceptor for fluorescence resonance energy transfer.In addition,the methyl pyrazolone group in NPM can undergo unique single-electron oxidation with·OH,making the prepared probe show good selectivity and sensitivity for the detection of·OH,and the detection limit is as low as 158 n M.The probe’s real-time imaging and sensor analysis of·OH in neuronal mitochondria show that hypoxia affects the regulation of mitochondria in redox homeostasis,and prolonged hypoxia（>30min）will cause irreversible disturbance of cell function.This leads to cell damage and even necrosis.In addition,it was found that hypoxia-induced mitochondrial·OH bursts may be regulated by acid-sensitive ion channels（ASIC1a channels）.The developed probe provides a potential method for studying the changes of·OH.In the second work,we synthesized a core-shell structure Fe₃O₄@SiO₂@UCNP magneto-optical bifunctional up-conversion nanomaterial and an amphiphilic photo-isomerized azobenzene derivative（Azo）,The two are self-assembled,so that they can be excited by NIR light to achieve drug release.980 nm near-infrared excitation makes Azo undergo reversible E/Z isomerization under the upconversion luminescence of UCNP,forming a molecular propeller to release the loaded drug doxorubicin（DOX）,and the magnetic Fe₃O₄core endows the composite probe with superparamagnetism.It is possible to control the position of the composite probe by applying an external magnetic field.The developed composite probe also has the potential to load other small molecule drugs,and is a potential multifunctional nano diagnosis and treatment platform.