Synthesis And Cell Imaging Of The Fluorescent Probe Based On The Novel Imidazole And Pyridine Fluorophore

Mercury is one of the toxic heavy metals,the mercury in nature and the mercury that people may be exposed to in their daily life,enter the human body directly through the respiratory tract,digestive tract and skin,or accumulate in the human body through the biological chain.It will brings serious harm to human body,such as kidney damage,cell dysfunction,nerve disorder and so on.Therefore,it is an urgent need to detect Hg²⁺in environment and biological samples quickly and sensitively.In recent years,the detection of Hg²⁺by fluorescence probe method has attracted wide attention because of its advantages of low cost,simple operation instrument,low detection limit and real-time monitoring.At present,the detection of Hg²⁺by fluorescence probe is mostly based on the change of single fluorescence signal,the detection results are easily disturbed by many variable factors,such as probe concentration and stability,pH value,temperature,solvent polarity and so on.The ratiometric fluorescence probe can detect Hg²⁺by the ratio of the fluorescence emission signal intensity of the donor and receptor.so that can reduce or even eliminate the interference of the probe itself and the outside environment to the detection,make the detection results more accurate.Sulfite is widely used in food anticorrosion,antimicrobial,antioxidant and other aspects because of its inhibition of non-enzymatic browning,enzymatic browning and bacterial growth.However,excessive intake of sulfite can also cause harm to human body,such as diarrhoea,headache,asthma and allergies,meanwhile the large amounts of sulfite released from industrial production,also have a serious impact on the environment.Therefore,it is of great practical significance to find a method or technique for the rapid and accurate detection of sulfite.Compared with the traditional analytical methods,such as spectroscopic method,chromatographic analysis method and electrochemical method,the fluorescent probe method is widely used to detect the SO₃^2-because of its advantages of high cost,low cost,real-time monitoring and so on.Compared with the conventional probe,ratiometric fluorescent probe by the ratio of two fluorescence emission peaks of donor and receptor to detect SO₃^2-,it can greatly reduce the error and improve accuracy.In view of the above requirements,two ratio fluorescent probes based on fluorescence resonance energy transfer（FRET）mechanism were constructed for the detection of Hg²⁺and SO₃^2-,and their optical properties and applications were studied.The content consists of the following two parts:1.The synthesis,optical properties and application of a FRET-based fluorescent probe TMUHg-1 for detection of Hg²⁺We designed and synthesized a FRET-based fluorescent probe TMUHg-1 for quantitative detection of Hg²⁺,this probe employed a novel fluorescent group imidazole[1,5-a]pyridine as energy donor and rhodamine B as energy acceptor.The probe can quickly detect Hg²⁺with high sensitivity and selectivity,the probe exhibited a strong fluorescence emission at 466nm,after adding 1 equivalent Hg²⁺,result in a decrease of fluorescence intensity at 466nm,and a new fluorescence emission peak occured at 584nm.The fluorescence intensity ratio(F₅₈₄/F₄₆₆)of the probe showed a good linear relationship with the concentration of Hg²⁺,and the detection limit of the probe was as low as 0.93nM.The probe can complete the response to Hg²⁺in 5min,and at the same time,the color of probe solution changed from colorless to red in the process of response.The probe can be used to detect Hg²⁺in the range of pH4-10,and has been successfully used in the imaging of biological cells with little cytotoxicity.2.Synthesis and optical properties of a FRET-based fluorescent probe for detection of SO₃^2-We have designed and synthesized a ratiometric fluorescent probe based on FRET for the detection of SO₃^2-,the probe responds to SO₃^2-by double bond addition.The probe can detect SO₃^2-with high selectivity and sensitivity,the probe exhibited a strong fluorescence emission at 580nm,after adding 10 equivalent SO₃^2-,result in a decrease of fluorescence intensity at 580nm,a new fluorescence emission peak appeared in 476nm and the fluorescent intensity increased gradually with the increase of SO₃^2-.The probe could complete the rapid reaction of SO₃^2-in 2 min,meanwhile the color of the probe changed from red to colorless during the response process,the color change was visible to the naked eye.