| Nucleic acids and proteins are important biology macromolecules. Nucleic acids are the basic genetic material of life, they play an important role in the action of growth, upgrowth, and reproduction of organism. There are connection between nucleic acids configuration and its function, which is relation to carcinogenic and anticancer activity. Proteins are abundant in organism and are indeed fundamental to life, and they almost attach themselves to all life action, the more complex of organism structure, the more various kinds and functions of proteins. So it is of special value to study the interaction of small molecules and biomolecules, the quantitative analysis of nucleic acids and proteins with high sensitivity and low detection limit are important in life science, biochemical medicament, food analysis and clinical analysis, which is helpful to design the new type of drug and study the toxicity of drug. This project is the forward position and hot point in biochemical and biophysical researches.This thesis focus on the development of new probes for nucleic acids and proteins and to establish sensitive methods for the quantitative determination of them, using the fluorescence and resonance light scattering (RLS) as the primary technique. The UV-visible spectrometry, circular dichroism (CD), Fluorescence lifetime, Transmission Electron Microscopy (TEM) techniques are also used to study the interaction mechanism. The main conclusions are listed as follows:In the first section, we summarize the progress of nanoparticles as luminescent probes for nucleic acid and protein and the analytical applications in bioanalysis.In the second section, L-Cys-NZnS are prepared and they are utilized in the study of the interaction between morin, L-Cys-NZnS and nucleic acids. From the research, we find that when L-Cys-NZnS is added to morin, the intrinsic fluorescence of morin is quenched, however, the fluorescence intensity of morin-L-Cys-NZnS is greatly enhanced when fsDNA or yRNA are added to the system. Based on this, a new fluorimetric method for the determination of nucleic acids is proposed. Under optimum conditions, the enhanced fluorescence intensity is proportion to the concentration of nucleic acids in the range of 7.0×10-8 -1 .0×10-5 g mL-1 for fish sperm DNA (fsDNA) and 9.0×10-8-5.0×10-6 g mL-1 for yeast RNA (yRNA), their detection limits (S/N = 3) are 2.0×10-8 g mL-1, 4.0×10-8 g mL-1, respectively. The interaction mechanisms are studied through many techniques, it is considered that there exists synergistic effects of groove binding and electrostatic interaction between morin-L-Cys-NZnS and nucleic acid, and the complex of morin-L-Cys-NZnS-nucleic acid is formed. L-Cys-NZnS and nucleic acid could provide a large viscosity environment for morin and its fluorescence lifetime is prolonged, leading to a large enhancement of fluorescence intensity of the morin-L-Cys-NZnS-nucleic acid system.In the third section, the resonance light scattering (RLS) enhancement effect of Eu3+-L-Cys-NZnS-proteins is studied. It is found that proteins can enhance the RLS intensity of Eu3+-L-Cys-NZnS, under optimum conditions, there are linear relationships between the enhancing extent of RLS and the concentration of proteins in the range of 8.0×10-8-1.4×10-5 g mL-1 for BSA, 8.0×10-8-1.2×10-5 g mL-1 for EA. The detection limits (S/N=3) of BSA and EA are 3.1×10-8 g mL-1 and 1.7×10-8 g mL-1, respectively. The interaction mechanism investigation indicates that after adding Eu3+ and L-Cys-NZnS to the proteins, surrounding environment in polarity is changed, resulting proteins conformation has changed, and formed a larger aggregates, so that the system RLS intensity is enhanced.In the fourth section, it is found that Ag nanoparticles (nanoAg) can further enhance the fluorescence intensity of quercetin (Qu)-nucleic acids system. Under optimum conditions, the enhanced fluorescence intensity is proportion to the concentration of nucleic acids in the range of 8.0×10-9-2.0×10-6 g mL-1 for fsDNA, 2.0×10-8-8.0×10-6 g mL-1 for salmon serum DNA (smDNA) and 5.0×10-8-5.0×10-6 g mL-1 for yeast RNA (yRNA). The detection limits (S/N = 3) of fsDNA, smDNA and yRNA are 4.2×10-9 g mL-1, 1.2×10-8 g mL-1 and 6.6×10-9 g mL-1, respectively. Samples are satisfactorily determined. The interaction mechanism of the system isstudied using fluorescence, UV-Visible absorption (UV-Vis), Resonance light scattering (RLS) and transmission electron microscope (TEM) technology, indicating that there exists cooperation of groove binding and electrostatic interaction between Qu-nanoAg and nucleic acids and the complex of Qu-nanoAg-nucleic acids is formed.The chief characteristics of this thesis are as follows:1. It is found that L-Cys-NZnS can further enhance the fluorescence intensity ofmorin-nucleic acids system and provide a stable, sensitive and highly stable against fluorescent photobleaching fluorimetric method for the determination of nucleic acids. The complex of morin-L-Cys-NZnS-nucleic acid is formed.2. It is found that proteins can obviously enhance the RLS intensity of Eu3+-L-Cys-NZnS, this method is simple, stable and quick.3. It is found that nanoAg can further enhance the fluorescence intensity ofQu-nucleic acids system and provide a simple and sensitive fluorimetric method for the determination of nucleic acids. The complex of Qu-nanoAg-nucleic acids was formed.
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