Synthesis And Bioanalytical Applications Of Redox Stress Fluorescent Probes

NADH(reduced coenzyme ?)is a coenzyme involved in many important redox reactions in organisms.NAD⁺is the oxidized form of NADH.Studies have shown that changes in the number ratio and concentration of NAD⁺/NADH are closely related to many diseases,such as cancer,anemia,diabetes and other major human-related diseases.At present,the reported fluorescent probes for detecting NADH are mainly based on the short-wave excitation and emission.Due to the high energy of shortwave,it will cause serious damage to biological samples,example:1)Background light interference,because NADH has fluorescence,and some amino acid residues can also emit fluorescence after being excited by short-wave light,resulting in strong background interference;2)The damage to the cell and tissue is serious.Short-wave light damages cells and tissues,and non-radiation relaxation leads to the generation of free radicals(singlet oxygen);3)The penetration of Short-wave light is weak,it is easily absorbed by substances in cells.Thus,it is important to design a highly sensitive fluorescent probe with near-infrared emission.Hypochlorous acid is a powerful defense weapon for the human immune system.However,when the hypochlorous acid in the body is excessive,it will cause oxidative stress damage,which will lead to many diseases.Fortunately,there are many reductive substances in the body that can repair this oxidative stress damage.Due to the short retention time of HClO and SO₂in the body,it is difficult to detect the changes of them in the body.The current fluorescent probes for hypochlorous acid and sulfur dioxide have some limitation:1)Low-response for successive detection 2)Low sensitivity for successive detection.Based on the above points,we performed the following works in this thesis.Chapter 1 We have reviewed the fluorescent probes for detecting NADH,hypochlorous acid(HClO),sulfur dioxide(SO₂)and their derivatives in recent years.Chapter 2 A highly sensitive fluorescent probe with near-infrared emission via quinolone working identification group was designed and synthesized.The probe has a good linear relationship with NADH,and the lower detection limit is 20 nM.When the probe is combined with NADH,the product emission peak is at 624 nm,and excitation waveleng is at 514 nm.The large Stokes shift is 124 nm.Low cytotoxicity(the probe:0-30?M,cell Viability:95(4)).Chapter 3 We designed and synthesized the probe THOS.When THOS responds to hypochlorous acid and sulfur dioxide,it shows on-off-on fluorescence signal.The probe has fast response(HClO:<10 s;SO₂:<20 s),low detection limit(HClO:LOD=10 nM;SO₂:LOD=3 nM),and low cytotoxicity(the probe:0-45?M,cell Viability(25)90%(8)(13)Chapter 4 This paper summarizes the work and prospects of future research.