| Seminconductor.nanoparticles have attracted considerable interests in biology, analytical science and medical field because of their unique physical and chemical properties.The preparation of the novel nanoparticles with good fluorescent properties for biologic analysis are absolutely necessarily.In the thesis,new type of semiconductor nanoparticles were synthesized in aqueous solution by colloid chemical method,and their application as biological fluorescent probes were investigated.The results and conclusions of research in this dissertation are as followings:1.The water-soluble CdSe/CdS nanoparticles were synthesized successfully in the aqueous solution by using citrate as the stabilizer.The influences of preparation conditions,including reaction temperature,reaction time,pH,molar ratios of reactants,on the fluorescence characterization of CdSe/CdS nanoparticles were investigated in detail by fluorescence spectrum.The optimized preparation conditions were obtained.The structure,size,shape,component and spectral property of the nanoparticles were characterized by transmission electron microscope(TEM),X-ray diffraction(XRD), infrared spectrum(IR),UV-Vis absorption spectrum(UV-Vis)and photoluminescence (PL).The results showed that this water-soluble,biocompatible CdSe/CdS nanocrystals have good fluorescent property.2.The novel water-soluble core/shell/shell structural CdSe/CdS/ZnS nanoparticles were synthesized successfully in aqueous solution by using L-cysteine as the stabilizer. The influences of preparation conditions on the fluorescence characterization of CdSe/CdS/ZnS nanoparticles were investigated in detail by fluorescence spectrum.The optimized preparation conditions were obtained.The structure,size,shape,component and spectral property of the nanoparticles were characterized by TEM,XRD,IR,UV-Vis and PL.The results showed that CdSe/CdS/ZnS nanoparticles surface-modified with L-cysteine have good fluorescent property.The cysteine modified on the surface of the nanocrystals renders the nanocrystals good water-soluble and biocompatible.The novel CdSe/CdS/ZnS nanocrystals appear many advantages such as stability,water-soluble, biocompatible and high fluocescence intensity.3.Based on the fluorescence quenching of water-soluble CdSe/CdS/ZnS core/shell/shell nanoparticles by ct-DNA,a new method was founded for the rapid determination of ct-DNA by using water-soluble CdSe/CdS/ZnS core/shell/shell nanoparticles as a novel fluorescence probe.Under the optimal conditions,the fluorescence quenching intensity of the system is linear with the concentration of ct-DNA in the range of 10～650μg·L-1(r=0.9993).The detection limit is 2.8μg·L-1.This method is simple,rapid and sensitive. |
