| Nucleic acids and proteins are basic of life. Nucleic acids are the genetic material, they play an important role in the action of every stage (growth, up-growth, and so on). Proteins are the most abundant in organism, and they almost attach themselves to all life action. 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.Based on the fluorescence and resonance light scattering (RLS) as the primary technique, 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, with multiple techniques to study the interaction mechanism. The main conclusions are listed as follows:In the first section, we summarize the recent development of fluorescent probes for nucleic acid, protein and the analytical applications. The progress of nanoparticles in the analysis of nucleic acid and protein is also commented.In the second section, Nucleic acids can greatly enhance fluorescence intensity of the kaempferol (Km)-Al(Ⅲ) system in the presence of silver nanoparticles (AgNPs). Based on this, a novel method for the determination of nucleic acids is proposed. Under studied conditions, there are linear relationships between the extent of fluorescence enhancement and the concentration of nucleic acids in the range of 5.0×10-9-2.0×10-6 g ml/1 for fish sperm DNA (fsDNA),7.0×10-9-2.0×10-6 g mL/1 for salmon sperm DNA (smDNA) and 2.0×10-8-3.0×10-6 g mL-1 for yeast RNA (yRNA), and their detection limits are 2.5×10-9 g mL-1,3.2×10-9 g mL-1 and 7.3×10-9 g mL-1, respectively. Samples were satisfactorily determined. The results indicate that the fluorescence enhancement should be attributed to the formation of Km-Al(Ⅲ)-AgNPs-nucleic acids aggregations through electrostatic attraction and adsorption bridging action of Al(Ⅲ) and the surface-enhanced fluorescence effect of AgNPs.In the third section, the RLS enhancement effect of Lin-AgNPs-nucleic acid is studied. It is found that DNA can enhance the RLS intensity of Lin-AgNPs. Under studied conditions, there are linear relationships between the enhancement extent of RLS and the concentration of nucleic acid in the range of 3.0×10-8-7.0×10-7g mL-1 for yRNA,3.0×10-8-3.0×10-7 g mL-1 for smDNA. The detection limits (S/N=3) of yRNA and smDNA are 1.1×10-8 g mL-1 and 6.6×10-9 g mL-1, respectively. The interactions in the system of Lin-AgNPs-nucleic acid are electrostatic interaction mainly.In the fourth section, Py is determined by RLS technology using AgNPs as probe. The addition of Py can enhance the RLS of AgNPs. A novel and simple method for Py detection is found.In the fifth section, it is found that protein can enhance the fluorescence intensity of Km-Al(Ⅲ)-SDBS-BSA. Under studied conditions, the enhanced fluorescence intensity is proportion to the concentration of proteins in the range of 9.0×10-8-1.0×10-5 g mL-1 for BSA,5.0×10-7-1.0×10-5 g mL-1 for EA when the excitation wavelength is at both 417 nm and 260nm. The detection limits (S/N=3) of BSA and EA are 1.0×10-8g mL-1,1.6×10-7 g mL-1 (λe= 417 nm) and 2.0×10-8g mL-1,1.5×10-7 g mL-1 (λe= 260nm) respectively. Samples are satisfactorily determined. The fluorescence enhancement of the system originates from the formation of Km-Al(Ⅲ) complex and the hydrophobic microenvironment provided by BSA and SDBS.The chief characteristics of this thesis are as follows:1. It is found that Nucleic acids can greatly enhance fluorescence intensity of the kaempferol (Km)-Al(Ⅲ) system in the presence of silver nanoparticles (AgNPs) and improve the sensitivity of the syetem of Km-Al(Ⅲ)-nucleic acid. And the system of Km-Al(Ⅲ)-AgNPs was used as a fluorescence staining reagent for sensitive DNA detection by DNA pattern of agarose gel electrophoresis analysis.The mechanism of the system was also discussed in detail. 2. It is found that nucleic acid can obviously enhance the RLS intensity of Lin-AgNPs, this method is simple, stable and quick.3. RLS technology is used for the determination of Py. And a novel and simple method is found.4. The fluorescence enhancement of the system of Km-Al(Ⅲ)-SDBS-BSA is studied. Flavoniods are used as fluorescence probe in the advantages of low toxity. |
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