Design And Synthesis Of Organic Small Molecule Probes And Its Application In Bioimaging

In recent years,organic small molecule fluorescent probe,used as a high sensitivity,high selectivity,low cost,avoid damage detection methods,which can achieve the target in situ,real-time,visual inspection,especially in biological imaging application.Now fluorescent probes are widely used by the group around the world,such as various types of target molecules tracer markers,physiological process testing and clinical medical analysis and so on.Fluoride ion as the smallest ion radius of the anion,which have the strongest electronegativity,it also is an indispensable trace elements in the body,shows a very important physiological function.Fluorine is one of composition of bone and is the essential elements of the teeth.The lack of fluoride in the human body may lead to osteoporosis,dental caries and other diseases;however,excessive fluoride in body may cause fluoride bone disease,dental fluorosis and other diseases.In view of this,it has a very important significance in research to detection of fluoride ions.Hydrogen peroxide,as one of active oxygen species,which is producted through the cytokines,neurotransmitters stimulate the activation of NADPH oxidase complex.H2O2 have a very important role in the immune process,cell signaling,cell senescence,apoptosis and other physiological processes.Recent years,studies have found that abnormal hydrogen peroxide content have very closely linked with cancer,diabetes,neurodegenerative diseases and cardiovascular and cerebrovascular diseases.Two-photon fluorescent probes have many advantages.Such as low background interference and strong penetrating ability,so they are more suitable for living cells and tissue imaging than single photon probe.Based on this,our group designed and synthesized a two-photon fluoride ion probe with tert-Butyldimethylsilyl chloride as the recognition group.The fluorescence enhancement was about 10 times.The probe has many advantages.Such as good selectivity,high sensitivity,low detection limit,low cytotoxicity,good biocompatibility and good water solubility.The detection limit of fluoride ion is as low as 7.8×10-7 M.The probe molecule has been successfully applied in human cervical cancer cells(HeLa)one-photon and two-photon imaging,and the first application of fluoride ion fluorescent probe in mouse tissue imaging.In the second part of the paper,our group used boronate as a recognition group designed and synthesised a two-photon hydrogen peroxide probe,the fluorescence enhanced about 40 times,the probe can specifically identify the active oxygen species hydrogen peroxide with fast response,high sensitivity,low detection limit.Tested by the test,the detection limit of the probe is calculated to be 1.46×10-7 M.The probe has been used in endogenous and exogenous cell imaging and mouse tissue imaging.In the third part of the paper,we synthesised two kinds of phenanthrene imidazole fluorophores for hydrogen peroxide based on 4-phenylphenol and 4-Hydroxy-4-biphenylcabonitrile.The phenanthrene imidazole fluorophore have many advantages,such as high fluorescence quantum yield and large stokes shift.The two probes show excellent properties include response quickly,high sensitivity,low detection limit and so on.The detection limits for hydrogen peroxide were 1.48×10-7 M,1.08×10-7 M.Respectively,the probes have been successfully used in endogenous and exogenous cell imaging of HeLa cells,OGD/R experient and in vivo imaging of mice.