Sulfide Nanocomposites Templated Synthesis And Applications

In recent years, using semiconductor nanopaticles instead of organic fluorescent dye as fluorescent biological labels has made great progress. During the process of the experiment, templated-synthesis of DNA/CdS nanocomposites and core-shell structures of DNA/CdS/ZnS has been described.The synthesized nanocomposites have great water-solubility, stability and special fluorescence property. The morphologic and spectral characterizations of these nanocomposites indicate that the DNA/CdS nanomaterials have a higher density of surface state with an enhanced photoluminescence (PL) intensity. While the core-shell structure exhibits a better biocompatibility. The synthetic approach described herein may be extended to other types of DNA-semiconductor conjugates with tailored properties for diverse applications.The nanocomposites hold great potential in applications such as biological imaging.The results for preparing and characterizing these nanomaterials are as follows:1.DNA templated-synthesis of DNA/CdS nanocomposites with three different methods has been described. CdS coating adsorb onto the DNA template through electrostatic interaction. The resulting nanomaterials are stable and water-soluble with a high fluorescence efficiency.2.With the encapsulation of ZnS on the surface of the DNA/CdS nanocomposites,core-shell structures of DNA/CdS/ZnS have been synthesized.Higher stability and fluorescence efficiency of the core-shell structure can be resulted from higher density of surface state and lower structure defects.3.The above nanocomposites were characterized with AFM, TEM, UV/Vis, fluorescence spectrometry and resonance light scattering spectrometry. Potential applications of these nanomaterials in sequence-specific DNA analysis have been discussed.