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In this letter, we report a chemical route for synthesizing SiO@Au core-shell nanoparticles. The process includes four steps: (i) preparation of the silica cores, (ii) grafting gold nanoparticles over SiO cores, (iii) priming of the silica-coated gold nanoparticles with 2- and 10-nm gold colloids, and finally, (iv) formation of complete shell. The optical extinction spectra were experimentally measured and compared to numerical calculations in order to confirm the dimensions deduced from SEM images. Finally, the potential of such core-shell nanoparticles for biosensing was probed by means of surface-enhanced Raman scattering measurements and revealed higher sensitivities with much lower gold quantity of such core-shell nanoparticles compared to Au nanoparticles exhibiting similar diameters. [ABSTRACT FROM AUTHOR]

A particular interesting plasmonic system is that of metallic nanostructures interacting with metal films. As the localized surface plasmon resonance (LSPR) behavior of gold nanostructures (Au NPs) on the top of a gold thin film is exquisitely sensitive to the spacer distance of the film-Au NPs, we investigate in the present work the influence of a few-layered graphene spacer on the LSPR behavior of the NPs. The idea is to evidence the role of few-layered graphene as one of the thinnest possible spacer. We first show that the coupling to the Au film induces a strong lowering at around 507 nm and sharpening of the main LSPR of the Au NPs. Moreover, a blue shift in the main LSP resonance of about 13 nm is observed in the presence of a few-layered graphene spacer when compared to the case where gold nanostructures are directly linked to a gold thin film. Numerical simulations suggest that this LSP mode is dipolar and that the hot spots of the electric field are pushed to the top corners of the NPs, which makes it very sensitive to surrounding medium optical index changes and thus appealing for sensing applications. A figure of merit of such a system (gold/graphene/Au NPs) is 2.8, as compared to 2.1 for gold/Au NPs. This represents a 33 % gain in sensitivity and opens-up new sensing strategies. [ABSTRACT FROM AUTHOR]

Here we present an original process combining top-down and bottom-up approaches by annealing a thin gold film evaporated onto a hole template made by etching a PS–PMMA copolymer film. Such process allows a better control of the gold nanoparticle size distribution which provides a sharper localized surface plasmon resonance. This makes such route appealing for sensing applications since the figure of merit of the Au nanoparticles obtained after thermal evaporation is more than doubled. Such process could besides allow tuning the localized surface plasmon resonance by using copolymers with various molecular weights and thus be attractive for surface-enhanced Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Presents guidelines of the organizing committee Standards, Options and Recommendations for the use of appetite stimulants in oncology. Objectives of these guidelines; Definition of Standards, Options and Recommendations and level of evidence; Appetite stimulants that can use in patients with cancer.