Novel Au–SiO2–WO3 Core–Shell Composite Nanoparticles for Surface-Enhanced Raman Spectroscopy with Potential Application in Cancer Cell Imaging

This is the final version. Available on open access from Wiley via the DOI in this recordWith the rapid development of nanotechnology during the last decades, the ability to detect and control individual objects at the nanoscale has enabled to deal with complex biomedical challenges. In cancer imaging, novel nanoparticles (NPs) offer promising potential to identify single cancer cells and precisely label larger areas of cancer tissues. Herein, a new class of size tunable core-shell composite (Au-SiO2-WO3) nanoparticles is reported. These nanoparticles display an easily improvable ∼ 103 surface-enhanced Raman scattering (SERS) enhancement factor (EF) with a double Au shell for dried samples over Si wafers and several orders of magnitude for liquid samples. WO3 core nanoparticles of 20-50 nm in diameter are sheathed by an intermediate 10-60 nm silica layer, produced by following the Stöber basedprocess and Turkevich method, followed by a 5-20 nm thick Au outer shell. By attaching 4- mercaptobenzoic acid (4-MBA) molecules as Raman reporters to the Au, high-resolution Raman maps which pinpoint the nanoparticles’ location are obtained. Our preliminary results confirm their advantageous SERS properties for single-molecule detection, significant cell viability after 24 h and in vitro cell imaging using coherent anti-stokes Raman scattering (CARS). Our long-term objective is to measure SERS nanoparticles in vivo using NearInfrared light.Engineering and Physical Sciences Research Council (EPSRC

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Pulse measurement by time to frequency conversion with a quadratic

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Broadband similariton: features and applications

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International audienceUsing spectral-interferometry for short pulse complete characterization, we studied the similariton generated in single-mode fiber without gain due to the combined impacts of nonlinearity and dispersion. The nonlinear-spectronic nature of such a similariton, with the key specificity of linear chirping, leads to its self-spectrotemporal imaging, important for applications to signal analysis - synthesis problems in ultrafast optics