Design And Synthesis Of Small Biological Molecules Fluorescent Probes Based On Rhodamine Analogues And Its Bioimaging Application

Fluorescence imaging has become a very important technique for biological detection and physiological processes in the field of biology.Rescently,fluorescence imaging has become more and more important owing to the propery such as excellent sensitivity,outstanding selectivity and the simplicity of operation.With the development of technology,fluorescent probe has been applied to detect varieties of ions,small biological molecules,the pH of the environment and the viscosity.Rhodamine has been used as a fluorescent platform by modified as flourscent probe due to its superior photostability,photophysical properties and the high fluorescence quantum yield.Although fluorescent properties of rhodamine are excellent,its spectral range is mostly in visible range,which limits its application in biological organisms.Therefore,modifying the rhodamine structure to improve its photophysical properties,moveing the emission wavelength to near-infrared range is very important for its application in the biological field.In this paper,we designed the near-infrared and two-photon fluorescent probes by modifying the rhodamine.Moreover,the probes were used for detecting the small biological molecules.In the second chapter,we mainly introduce the near-infrared fluorescent probe CSCN-Cu for detecting Cu²⁺ based on the CSCN which is the derivative of rhodamine.Although many near-infrared fluorescent probes for Cu²⁺ have been reported,the fluorescence enhancement is between 10 and 20 folds.Upon addition of Cu²⁺ to the probe,the fluorescence enhancement is over 40 folds.Futherormore,the CSCN has good selectivity toward Cu²⁺.The probe CSCN-Cu not only responds to Cu²⁺ in the solution,but also detects Cu²⁺ in the cells.In the third chapter,we mainly introduce the near-infrared fluorescence probe CSBOH for detecting H₂O₂ based on the CSOH.H₂O₂ is one of most important active oxygen species?ROS?,it is essential for the physiological process.The human body is a weak alkaline environment,the pH value in some issue is about 8.0.H₂O₂ is more reactive in the alkaline environment.Therefore,the detection of H₂O₂ under alkaline conditions is also very important.The probe CSBOH is the first ratiometric near-infrared fluorescence probes that detect H₂O₂ in alkaline environments.After added H₂O₂,CSBOH exhibited remarkably different fluorescence change at 650 nm and 720 nm when excited by 560 nm and 670 nm light respectively in alkaline environment.The probe CSBOH can not only recognize the extracellular H₂O₂,but also respond to endogenously generated H₂O₂ in cells.What is more,the vivo experiment shown that the probe can detect H₂O₂ in living system.In the forth chapter,we designed and synthesized a novel two-photon fluorescence probe FR-TP which can well detect thiopenol.Thiophenols are a kind of compound which is highly toxic for human beings and is widely used in the field of organic synthesis.The probe FR-TP has good property such as high selectivity,rapid response and excellent sensitivity.FR-TP can respond to thiophenol within 100 s in buffer solution,and the limit of the detection of FR-TP is 0.363 ?M.Notably,the probe FR-TP has low cytotoxicity to living cells so that it can be used to visualize thiophenol in them with one-photon or two-photon modes.Furthermore,the probe can detect thiophenol in living tissues and be used to monitor biological thiophenol poisoning in the animal model of thiophenol inhalation by a two-photon microscope.Above all,this is the first red emissive two-photon probe for thiophenol which can detect biological thiophenol poisoning in the model of thiophenol inhalation.