Photochemical Synthesis of Gold Nanorods - Journal of …
Yu YY, Chang SS, Lee CL, Wang CRC: Gold nanorods: electrochemical synthesis and optical properties
Seed-Mediated Synthesis of Gold Nanorods: Role of …
We report studies on the synthesis of gold nanorods by a three-step seeding protocol method using a variety of different gold seeds. The synthetic method is adapted from one we published earlier (Jana et al. 2001, , 4065). The seeds chosen for these studies have average diameters in the range from 4 to 18 nm, with positively charged as well as negatively charged surface groups. In all the cases, along with a large concentration of long rods, a small number of different shapes such as triangles, hexagons, and small rods are observed. The proportion of small rods increases with an increase in the seed size used for nanorod synthesis. For long nanorods synthesized by different seeds a comparison of various parameters such as length, width, and aspect ratio has been made. A dependence of the nanorod aspect ratio on the size of the seed is observed. Increasing the seed size results in lowering of the gold nanorod aspect ratios for a constant concentration of reagents. The charge on the seed also plays a role in determining the nanorod aspect ratio. For positively charged seeds variation in the aspect ratio is not as pronounced as that for negatively charged seeds. The gold nanorods synthesized were characterized by transmission electron microscopy (TEM), UV−vis spectroscopy, and Fourier transform infrared spectroscopy. The role of seed size in the size and shape evolution of the nanocrystal, at different growth stages, has been studied by TEM.
Small gold nanorods (GNRs) with longitudinal plasmon absorption in the near-infrared window (700–900 nm) are of great interest for in vivo optical applications (e.g., photothermal therapy) and for their high-payload-to-carrier ratio for drug delivery. Common synthetic strategies for GNR production afford spherical and cubical nanoparticles in addition to the desired GNRs. Thus, several methods have been proposed for the selective separation of GNRs from the reaction by-products. For example, centrifugation has been used to separate the high aspect ratio (AR) GNRs (AR > 4). However, it is difficult to separate small sized GNRs with low AR (AR ≤ 4) that are particularly promising for biomedical applications. Here, we describe a simple and fast procedure for the separation of small GNRs with AR of 4, and length of 28 nm from reaction by-products.
Strategies for Preparing Albumin-based Nanoparticles …
Gold nanorods have been synthesized by photochemically reducing gold ions within a micellar solution. The aspect ratio of the rods can be controlled with the addition of silver ions. This process reported here is highly promising for producing uniform nanorods, and more importantly it will be useful in resolving the growth mechanism of anisotropic metal nanoparticles due to its simplicity and the relatively slow growth rate of the nanorods.
Mackey MA, Ali MR, Austin LA, Near RD andEl-Sayed MA: The most effective gold nanorod size for plasmonicphotothermal therapy: theory and in vitro experiments. J Phys ChemB. 118:1319–1326. 2014. : :
Surface modification, functionalization and …
Composite plasmonic nanoassemblies exhibit fascinating optical properties. One interesting application is their use in surface enhanced Raman scattering (SERS) [1, 2]. However, the chemical synthesis of plasmonic nanostructures with well defined geometries is still a challenge. In this contribution, anisotropic nanoassemblies, composed of gold nanorods (GNRs) as the core and gold nanoparticles (GNPs) as satellites, were synthesized (see Fig.1). Typical TEM images (Fig. 2A) of the nanoassemblies demonstrate their well-defined geometry. The position of the tunable localized surface plasmon resonance (LSPR) peak can be controlled by the aspect ratio of the core (GNR) and the size of the satellites (GNPs). Due to plasmonic coupling and the resulting hot spots in the particle junctions (FEM calculations, not shown), the nanoassemblies are excellent SERS substrates. Finally, we used the nanoassemblies for the detection of the cytokine interleukin-6 in a SERS immunoassay. IL-6 could be detected at concentrations as low as 0.1pg/mL with great specificity (Fig. 2B).
Funding by the Alexander von Humboldt foundation (AvH) and the Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged.
Among the various gold NPs, gold nanorods (GNRs) have attracted particular attention due to their unique properties (structural, optical, and electronic) . Moreover, facile and well-established synthetic routes (e.g., seed-mediated growth protocol ) permit to produce stable structures of GNRs with high yield and monodispersity.
International Journal of Nanomedicine - Dove Press
Volcanoes and volcanology | Geology
(a) Particle synthesis
Colloidal Gold Nanorods ; Synthesis and properties
Colloidal Gold Nanorods ; Synthesis and ..
Nanomedicine — NEJM
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