Preparation And Characteristic Of Nano-biocomposites

Nano-biocomposites combine the advantages of frontiers of science subjects such as nano-techniques and bio-techniques perfectly, which have the superior property that other materials cannot compete with. Nano-biocomposites have promising perspective of application in the fields such as targeted drug delivery system, early medical diagnose and tissue engineering. Research of their preparation and property plays an important role in the development of the materials. In this paper, the preparations for several kinds of nano-biocomposites with special functions were explored, and their properties were characterized.(1) SiO₂@Au composite nanoparticles have potential application in diagnose and treatment of cancer for its optical plasmon resonance. Usually, they were prepared through a 3-step method. Herein, biocompatible and hydrophilic macromolecules were used to simplify the process for fabricating SiO₂@Au composite nanoparticles. The influence of various polymers on the SiO₂@Au with different size of SiO₂ was analyzed by TEM and SEM, and UV-Vis spectrophotometer.(2)In this paper, using low-cost diesel oil as solvent, Monodispersed magnetite nanoparticles were prepared with modified thermal decomposition method, in which two step heating style was used. By changing distilled fractions in different reflux temperature, of diesel oil, monodispersed magnetite nanoparticles with a variable sizes from 3 to 20 nm in diameter could be synthesized. The particle size can also be enlarged by once or twice seed-mediated growth method, using the prepared magnetite nanoparticles as the seeds. This method is meaningful in the mass production of the monodispersed magnetite nanoparticles, as well as other metal oxide, at low-cost.(3) Bi₂S₃ is a novel nanoscale CT contrast agent; its efficiency depended on the size and morphology. In this paper, Bi₂S₃ colloidal nanocrystals were synthesized through a"hot injection"method. The size and morphology of Bi₂S₃ nanocrystals is highly dependent on the experimental parameters, including the reaction temperature, reaction time, reactant ratio and macromolecular dispersing ligands. There physical and chemical properties were characterized by TEM, SEM and XRD. The biological properties were also investigated by cell culture experiment. (4) Based on the previous study, the silica shells were used to coat the Bi2S3 nanocrystals. The silica shell enhanced the biological properties and stability of the nanocrystals. The Rhodamine B could be introduced in the silica shell to form the nano-composites with CT diagnose and fiuorescence diagnose. Further more, using the 3-step method, the Au shell were formed on the surface of silica coated Bi2S3 nanocrystals to synthesis the nano-composites with CT diagnose and tumor therapy.