Browsing by Subject "Gold nanorods"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Ground state depletion microscopy for imaging the interactions between gold nanoparticles and fluorescent molecules(2012-12) Blythe, Karole Lynn; Willets, Katherine A.; Brodbelt, Jennifer SGround state depletion with individual molecule return (GSDIM) super-resolution microscopy is used to interrogate the location of individual fluorescence bursts from two different nanoparticle-fluorophore systems. The first system consists of fluorophore-labeled DNA molecules on gold nanowire surfaces. In this system carboxytetramethyl rhodamine-labeled double-stranded DNA molecules were bound to the surface of gold nanowires via gold-thiol linkages. The second system focuses on mesoporous silica coated nanorods with dye embedded into the silica coating. The dye molecule, Rhodamine 6G, was incorporated into the silica shell during the nanorod coating procedure. Individual fluorescence bursts were spatially localized using point spread function fitting and used to reconstruct the image of the underlying nanowire or nanorod.Item Synthesis and characterization of carbon nanotubes, gold nanorods, silica coated nanocrystals, and binary nanocrystal superlattices(2009-05) Smith, Danielle Kristin; Korgel, Brian Allan, 1969-Nanomaterials such as carbon nanotubes, gold nanorods, magnetic nanocrystals, and binary nanocrystal superlattices have exciting potential applications. However, before these ideas can be applied, it is imperative to fully understand the materials synthesis. Multiwall carbon nanotubes were synthesized in supercritical toluene using cobaltocene, nickelocene, ferrocene, or metal nanocrystals as catalysts. Toluene served as both the solvent and carbon source for nanotube growth. The reaction was optimized by introducing supplemental carbon sources; either hexane or ethanol increased the yield relative to pure toluene and catalytic amounts of water minimized carbon filament and amorphous carbon formation. Gold nanorods were synthesized by the colloidal seed-mediated, surfactantassisted approach using cetyltrimethylammonium bromide (CTAB) obtained from ten different suppliers. The gold nanorod yield depended strongly on the CTAB used: with the same recipe, three of the CTABs produced only spherical particles, whereas the other CTABs produced nanorods with nearly 100% yield. Inductively coupled plasma mass spectrometry revealed a trace iodide impurity in the CTABs that did not yield nanorods. Further experiments introducing potassium iodide to the nanorod synthesis verified the detrimental effect of iodide on nanorod formation. Multifunctional colloidal core-shell nanoparticles of magnetic nanocrystals or gold nanorods coated with a fluorescent dye (Tris(2,2 -bipyridyl)dichlororuthenium(II) hexahydrate) doped silica shells were also synthesized. The as-prepared magnetic nanocrystals were initially hydrophobic and silica coated using a microemulsion approach, while the gold nanorods were hydrophilic and silica coated using a Stöber process. These colloidal heterostructures have the potential to be used as dual-purpose tags, exhibiting a fluorescent signal that could be combined with either dark-field optical contrast or enhanced contrast in magnetic resonance imaging. Binary superlattices (BSLs) of large iron oxide and small gold nanocrystals were assembled by slow evaporation of colloidal dispersions on tilted substrates. SEM and grazing incidence small angle X-ray scattering (GISAXS) confirmed the BSLs were simple hexagonal AB2 superlattices with long range order. GISAXS also revealed that the superlattice was slightly contracted perpendicular to the substrate as a result of solvent drying during the deposition process. Additionally, in some BSLs nearly periodic superlattice dislocations consisting of inserted half-planes of gold nanocrystals were observed.