Fabrication And Characterization The Water Soluble Nanorod Probes

With unique optical property, gold nanorods have promising prospects in medical, sensing, analytical chemical, which have become a hot topic in recent years. The unique optical property of gold nanorods is closely related to their size, shape and crystal structure. Surface plasmon resonance (SPR) of gold nanorods split into transverse mode (TSPR) and longitudinal mode (LSPR). The LSPR can be tuned across the visible region to the near-infrared region via increasing the length of the rods. For application of biochemical and medical fields, the gold nanorods should be water-soluble and stable in adverse conditions. Therefore, the study on the shape and surface modify of nanorods is very important.In this thesis, gold nanorods have been investigated from the following three aspects.Firstly, the terminal hydroxyl group of mPEG was changed into amino group, and carboxylic acid of the DNBA was activated with dicyclohexyl carbondimide(DCC) and p-nitrophenol to form all active ester.Amino of mPEG were introduced into molecular active ester of DNBA through functionalization to prepare mPEG-DNBA.Secondly, we report the preparation of water-soluble, surface-enhanced Raman scattering (SERS) -tagged gold nanorod probes. That was accomplished by direct ligand exchange of the initial stabilizer with a synthesized Raman-active poly(ethylene glycol) (PEG). The Au NR probes exhibited optimized SERS signals due to the coupling of the longitudinal surface plasmon resonance of the gold nanorods with the excitation wavelength. Furthermore, they were stable in adverse conditions because the outer PEG protecting layer provided steric stability to them. These multifunctional nanoprobes are expected to be widely applicated in biological analysis and biomedicine.Thirdly, the uniform size of gold nanorods were prepared by the seed-mediated method. The UV-vis spectroscopy and transmission electron microscopy(TEM) and were used to study the structural properties of gold nanorods taken from controlling the tempreture of solutions water baths and the concetration of the Cl-.