Synthesis And Biological Application For Bioimaging Of Reaction-based Small Molecular Probes

There are various of small molecules in organisms,such as glucose,amino acids,hydrogen sulfide(H2S),oxygen and reactive oxygen species(ROS)and so on,and these small molecules play an extremely important role in life process,such as anti-tumor,anti-inflammation,anti-aging etc.The main contents of this paper are the synthesis and biological applications for bioimaging of reaction-based small molecule probes for the determination of sulfur dioxide derivatives,hypochlorite and pH value.Based on different reaction mechanisms,three kinds of small-molecule fluorescent probes were designed and synthesized for the detection of SO32-,ClO-and pH value in vivo respectively.The artical includes four chapters,and its main contents are as follows:In chapter 1.The reactive oxygen species,biological function and the research progress of fluorescent probe detection are introduced.The biological functions of major active oxygen-sulfur dioxide derivatives and hypochlorite,the research status and significance of fluorescence probe detection are also summarized.The research progress of pH fluorescence probe is introduced as well.Finally,the main research ideas of this paper are put forward based on this.In chapter 2.Sulfite and bisulfite(SO32-/HSO3-)are the derivatives of sulfur dioxide(SO2),and their levels generally indicate the activity level and toxicity level of SO2.High levels of sulfite may cause diarrhea,hypotension,allergies,neurological diseases,lung cancer etc.Based on the coumarin skeleton,fluorescent probe DTCC is synthesized using aldehyde group as a recognition group.The probe itself has a large π-conjugated system with a weak fluorescence emission peak at 475 nm.When SO32-or HSO3-is added to the system,the aldehyde group on the probe structure is nucleated with SO32-/HSO3-,and the resulting compound has a strong fluorescence emission peak at same emission wavelength.Thus,the selective detection of SO32-/HSO3-is realized,and the linear range of SO32-concentration detection of probe DTCC is 0-100 μM with the detection limit of 0.23 μM,and this probe could be used for fluorescence imaging analysis of SO32-in HeLa cells successfully.In chapter 3.Hypochlorite(ClO-)is an important reactive oxygen species in the body and plays an important role in the body’s immune system.CIO-over-accumulation in vivo could lead to Parkinson’s disease(PD),Atherosclerosis,Angiocardiopathy etc.Therefore,it is of great significance to design and synthesize a new type of fluorescent probe to detect ClO-.In this chapter,we synthesized fluorescence probe ADT-MAM with diamino-maleonitrile as the recognition group using naphthone as the base skeleton.The probe itself showed a weak fluorescence effect.When ClO-was added to the system,strong fluorescence signal could be observed at 500 nm.The fluorescence intensity at this wavelength has a good linear relationship with the concentration of ClO-in the range of 0-24 μM,with a detection limit of 0.15 μM.This probe could be used for fluorescence imaging analysis of ClO-in HeLa cells and A549 cells successfully.In chapter 4.Acid-alkali balance plays a crucial role in the normal physiological processes,and abnormal pH level in cells could trigger a range of diseases,including cell dysfunction,cancer,rheumatoid arthritis and Alzheimer’s disease,etc.This highlights the importance of accurately detecting pH changes within cells.On the basis of chapter 3,a novel fluorescence probe DDTM with malononitrile as the reactive group was designed and synthesized using naphthone.The probe itself has no fluorescence,but after adding PBS buffer solution with different pH to the reaction system,the fluorescence intensity of the mixed system increased gradually at 578 nm as the pH increased.The probe could measure different pH environments conveniently and sensitively,and has a linear relationship in the pH range of 9.5-10.7,with a pKa value of 9.92.The probe could be used in the preparation of pH test strips practically and has good performance in HeLa cells imaging effect.