The Synthesis And Design Of Ratiometric Fluorescent Probes And Studies On The Biological Applications

Fluorescence analysis has the advantages of simple operation,low cost,high selectivity and short response time,then it has been widely used in the biomedical field.However,in the actual sample detection process,the results of fluorescence analysis are easily impaired by the interference of factors,such as instrument parameters,micro environment,probe concentration,and photobleaching.As a new type of fluorescence detection technology,the proportional fluorescence analysis method can well avoid the above interference factors and greatly improve the accuracy of the analysis results.The main research work of this dissertation is based on fluorescence resonance energy transfer（FRET）and excited-state intramolecular proton transfer（ESIPT）to design and synthesize proportional fluorescent probes that can be applied to the detection of biological samples.The full text is divided into the following four parts:1)Briefly elaborated the research background related to this dissertation.The main recognition mechanism of fluorescent probes and the current research status of fluorophores and tetracycline,cysteine,and Fe³⁺ions fluorescent probes are introduced.2)We prepared silicon nanoparticles（SiNPs）using a one-step microwave method and coordinated with Eu³⁺ions to prepare probe SiNPs-Eu.With the addition of tetracycline（TC）,the Eu³⁺ions in the probe binds with tetracycline to form the complex Eu-TC and emits a characteristic peak of Eu³⁺ions.Because of the existence of the FRET effect,the fluorescence intensity of SiNPs as an energy donor gradually decreases,the complex Eu-TC as the energy receptor fluorescence intensity is continuously enhanced,thus achieving the tetracycline ratio detection.The probe can be used for the detection of tetracycline in mouse serum and milk samples.3)We successfully designed and synthesized a novel proportional fluorescence probe based on the ESIPT principle and used to detect cysteine.When the probe is added cysteine in 20 m M PBS buffer（pH=7.4,DMSO:H₂O=1:4,v/v）,as the“open”ESIPT process makes the tautomers（T*emission）at long wavelengths continue to increase.However,the normal isomer（N*emission）at the short wavelength gradually decreased and the cysteine ratio is detected.The probe has a short response time and can be fully reacted in 15 minutes.Then can distinguish between homocysteine（Hcy）and glutathione（GSH）,other amino acids that are similar in structure.In addition,we have also successfully applied this probe to fluorescence confocal imaging of endogenous and exogenous cysteine cells.4)We designed and synthesized a proportional fluorescence Fe³⁺ions probe An-MNP based on the FRET with a naphthalimide dye as a precursor.The probe preparation method is simple,low cost,wide linear range and Fe³⁺ions can be rapidly and sensitively detected at the physiological pH.In addition,the compound MNP can also realize"off-on"detection of Fe³⁺ions by visible light excitation,and can be applied to subcellular imaging.Therefore,this new type of Fe³⁺ions fluorescent probe has a certain potential biological application value.