We report studies on the growth of gold nanoparticles by a seed-mediated approach in solution. The synthetic method is adapted from one we published earlier （Ashkarran et al. Appl. Phys. A 2009, 96, 423）. The synthe...We report studies on the growth of gold nanoparticles by a seed-mediated approach in solution. The synthetic method is adapted from one we published earlier （Ashkarran et al. Appl. Phys. A 2009, 96, 423）. The synthesized gold nanoparticles were characterized by X-ray diffraction （XRD）, dynamic light scattering （DLS）, UV-Vis spectroscopy, optical imaging and atomic force microscopy （AFM）. Optical absorption spectroscopy of the prepared samples at 15 A arc current in HAuCI4 solution shows a surface plasmon resonance around 520 nm. It is found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal nanoparticles. The intensity of the plasmonic peak of the prepared gold nanoparticles for 1 minute arc duration gradually increases due to seed mediation for up to 6 hours. The formation time of gold nanoparticles at higher seed concentrations is less than that at lower seed concentrations.展开更多
Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid...Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid molecules of various families (DNA and poly(I)xpoly(C)). This Au-size-dependent process is accompanied by a decrease in amplitudes of abnormal bands in the CD spectra specific to initial cholesteric liquid-crystalline dispersions and simultaneously by an appearance of plasmon resonance band in visible absorption spectrum. The study of properties of particles of cholesteric liquid-crystalline dispersion treated with Au-nanoparticles by means of various physico-chemical methods demonstrates that incorporation of Au-nanoparticles into quasinematic layers of these particles results in two effects: i) it facilitates reorganization of the spatial cholesteric structure of particles, and ii) it induces the formation of Au-clusters in the content of particles. It is not excluded that these effects represent a possible reason for genotoxicity of Au-nanopar- ticles.展开更多
文摘We report studies on the growth of gold nanoparticles by a seed-mediated approach in solution. The synthetic method is adapted from one we published earlier （Ashkarran et al. Appl. Phys. A 2009, 96, 423）. The synthesized gold nanoparticles were characterized by X-ray diffraction （XRD）, dynamic light scattering （DLS）, UV-Vis spectroscopy, optical imaging and atomic force microscopy （AFM）. Optical absorption spectroscopy of the prepared samples at 15 A arc current in HAuCI4 solution shows a surface plasmon resonance around 520 nm. It is found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal nanoparticles. The intensity of the plasmonic peak of the prepared gold nanoparticles for 1 minute arc duration gradually increases due to seed mediation for up to 6 hours. The formation time of gold nanoparticles at higher seed concentrations is less than that at lower seed concentrations.
文摘Au-nanoparticles (size about 2 nm, but not 5 or 15 nm) are capable of effectively incorporating into quasinematic layers of particles of cholesteric liquid-crystalline dispersion formed by double-stranded nucleic acid molecules of various families (DNA and poly(I)xpoly(C)). This Au-size-dependent process is accompanied by a decrease in amplitudes of abnormal bands in the CD spectra specific to initial cholesteric liquid-crystalline dispersions and simultaneously by an appearance of plasmon resonance band in visible absorption spectrum. The study of properties of particles of cholesteric liquid-crystalline dispersion treated with Au-nanoparticles by means of various physico-chemical methods demonstrates that incorporation of Au-nanoparticles into quasinematic layers of these particles results in two effects: i) it facilitates reorganization of the spatial cholesteric structure of particles, and ii) it induces the formation of Au-clusters in the content of particles. It is not excluded that these effects represent a possible reason for genotoxicity of Au-nanopar- ticles.
