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Galvanic Replacement Reactions (galvanic + replacement_reaction)
Selected AbstractsGold Nanocages for Biomedical Applications,ADVANCED MATERIALS, Issue 20 2007E. Skrabalak Abstract Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl4. The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where the optical attenuation caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometer-sized agents for cancer diagnosis and therapy. [source] From Ag Nanoprisms to Triangular AuAg NanoboxesADVANCED FUNCTIONAL MATERIALS, Issue 8 2010Damian Aherne Abstract In recent years, galvanic replacement reactions have been successfully employed to produce hollow bimetallic nanostructures of a range of shapes, yet to date there has been no example of the formation of hollow triangular AuAg nanostructures from a Ag nanoprism template. In this manuscript the first example of the synthesis of enclosed triangular AuAg nanostructures (triangular nanoboxes) via galvanic replacement reactions from Ag nanoprisms is reported. These triangular nanoboxes are studied by TEM and HAADF-STEM imaging to elucidate their structure. These studies show that the nanostructures are hollow and do not consist of a Ag core surrounded by a Au shell. Discrete dipole approximation calculations for the extinction spectra are carried out and provide additional evidence that the nanostructures are hollow. These new triangular nanoboxes are very attractive candidates for encapsulation and transport of materials of interest such as drugs, radioisotopes, or magnetic materials. [source] Synthesis and Characterization of Noble-Metal Nanostructures Containing Gold Nanorods in the CenterADVANCED MATERIALS, Issue 6 2010Eun Chul Cho Noble-metal nanostructures containing gold (Au) nanorods in the center were synthesized by employing Au nanorods as templates for epitaxial growth of silver (Ag). The immediate products, Au@Ag core,shell nanocrystals with an octahedral shape, were transformed into noble-metal (Au, Pd, and Pt) hollow nanostructures containing Au nanorods in the center, via galvanic replacement reactions (see figure). [source] "Remote" Fabrication via Three-Dimensional Reaction-Diffusion: Making Complex Core-and-Shell Particles and Assembling Them into Open-Lattice CrystalsADVANCED MATERIALS, Issue 19 2009Paul J. Wesson Reaction-diffusion (RD) processes initiated from the surfaces of mesoscopic particles can fabricate complex core-and-shell structures. The propagation of a sharp RD front selectively removes metal colloids or nanoparticles from the supporting gel or polymer matrix. Once fabricated, the core structures can be processed "remotely" via galvanic replacement reactions, and the composite particles can be assembled into open-lattice crystals. [source] | ||||||||||