Synthesis And Application Of Near-infrared Fluorescent Dyes Used For Biological Analysis

The development of life science is a process of a deeper and wider study of the species which make up of organisms (such as protein, DNA, sugar, metal ion, anion and neutral molecular). In this process, a basic problem is how to detect and identify these species. Fluorescent dye is an ideal labeling reagent because it can give off light signal, do less harm to organism. They play more and more important roles during the development of life science, so much attention has been attraceted to study the fluorescent dyes.Owing to high sensitivity and excellent selectivity, the method of fluorescent spectroscopy detection is widely used in analytical chemistry, especially in biological analysis. In recent years, near-infrared (NIR) fluorescent dyes (excited at 650-900 nm) appealed more attention because of some advantages. For example, they can avoid the background absorption, fluorescence and light scattering to increase the detection sensitivity. Also, they could do less damage to the biosysterm along with the availability of low-cost sources of irradiation. Thus, recent developments in medical and biological research have stimulated great interest in design and preparation of NIR fluorescent dyes. However, many problems were encountered with the preparation and application of the NIR fluorescent dyes, such as aggregation, photobleaching and low fluorescence quantum yields. So it is necessary to synthesize novel and more effective dyes that absorb and emit in the NIR region. At present, the widely used dyes in biological analysis are rhodamine, BODIPY, cyanine, coumarin and so on. Among them, the absorption and emission wavelengths of cyanine dyes are mostly in the region of 600-800 nm, even beyond of 800 nm, so when they are used as probes, they can achieve the absence or reduction of background absorption, fluorescence and light scattering to improve the detection sensitivity. And rhodamine and BODIPY dyes attract more and more attention because of their good photostability, high fluorescence quantum yields and insensitivity to pH.The following are the main content of this dissertation:One : Reviews were given firstly on the categories,properties and the applications of the fluorescent dyes in analytical chemistry, life science and other fields.Two: Synthesized a novel rhodamine derivative with a single amidogen, then analyzed and characterized the dye by 1H NMR and EI-MS. We also studied the spectra of the dye and determined the fluorescence quantum yields in different solvents. Also discussed its photostability and sensitivity to different pH. The results showed that it can be used as a polarity probe to label protein.Three: Synthesized a novel BODIPY dye which emitted in the near-infrared region. And characterized the dye by 1H NMR, IR and EI-MS. We also studied the spectra of the dye and determined the fluorescence quantum yields in different solvents. Also discussed its photostability and its sensitivity to different pH. It can be used as an alkaline pH probe.Four: Designed and synthesized a novel fluorescent dye in the near-infrared region. The probe showed wide excitation and emission spectrum. The analytical experiment illustrated that it could detect copper ion with high sensitivity and selectivity. And it could realize the imaging of copper ion in living cells.