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Due to the good transparency of the human tissue in the biological spectral window, near-infrared (NIR)-dye loaded nanosystems enable more effective light-activated therapy and better contrast imaging with major impact on nanomedicine. Herein, we prepare Pluronic coated gold nanoparticles incorporating the hydrophobic NIR dye, IR780 iodide (GNP-Plu-IR780) to provide water-solubility and stability and demonstrate the proficiency of combining photodynamic and photothermal therapeutic activity with surface-enhanced resonance Raman scattering (SERRS) imaging facility. The potential of GNP-Plu-IR780 to operate as NIR-activatable agents was first assessed in aqueous solution by singlet oxygen generation measurements and monitoring the temperature increase of the nanoparticles. Subsequent in vitro uptake studies by dark field and differential interference contrast (DIC) microscopy reveal massive internalization of GNP-Plu-IR780 by murine colon carcinoma cells (C-26). Moreover, by exploiting the SERRS effect under 785 nm laser excitation we were able to perform intracellular tracking of GNP-Plu-IR780. Finally, NIR irradiation experiments conducted in vitro against C-26 cells show efficient phototherapeutic activity induced by GNP-Plu-IR780 with no dark cytotoxicity. Moreover, when compared to the administration of free drug or non-loaded GNP-Plu, the higher phototherapeutic activity of GNP-Plu-IR780 indicates the occurrence of cooperative synergistic effects by simultaneous photodynamic and photothermal activity.

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Early medical diagnostic in nanomedicine requires the implementation of innovative nanosensors with highly sensitive, selective, and reliable biomarker detection abilities. In this paper, a dual Localized Surface Plasmon Resonance - Surface Enhanced Raman Scattering (LSPR- SERS) immunosensor based on a flexible three-dimensional (3D) gold (Au) nanocups platform has been implemented for the first time to operate as a relevant "proof-of-concept" for the specific detection of antigen-antibody binding events, using the human IgG - anti-human IgG recognition interaction as a model. Specifically, polydimethylsilane (PDMS) elastomer mold coated with a thin Au film employed for pattern replication of hexagonally close-packed monolayer of polystyrene nanospheres configuration has been employed as plasmonic nanoplatform to convey both SERS and LSPR readout signals, exhibiting both well-defined LSPR response and enhanced 3D electromagnetic field. Synergistic LSPR and SERS sensing use the same reproducible and large-area plasmonic nanoplatform providing complimentary information not only on the presence of anti-human IgG (by LSPR) but also to identify its specific molecular signature by SERS. The development of such smart flexible healthcare nanosensor platforms holds promise for mass production, opening thereby the doors for the next generation of portable point-of-care devices.

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A high-end correlated spectral and imaging multianalysis, adapted for bidimensional systems, is presented here to analyze graphene oxide (GO) and reduced GO (rGO) modified with pyrene carboxylic acid (PCA). Confocal Raman mapping was used next to two-photon excited Fluorescence Lifetime Imaging Microscopy (FLIM) to characterize the distribution of PCA on GO and rGO and compared to UV-vis and X-ray Photoelectron Spectroscopy (XPS) analysis of the materials. Raman imaging clearly highlights the difference in the spatial distribution of PCA molecules on GO and rGO. Two-photon excited FLIM helped in gaining insight into the elusive phenomena and effects occurring at the GO-PCA interface level. Apart from the charge transfer effects from PCA molecules to GO, the GO structure depends on the molecular orientation and the spatial distribution of PCA molecules identified by different sp2 network domains in Raman mapping. Heating of GO-PCA results in an enhancement of the sp2 network presumably as the PCA aromatic core becomes fused into the GO nanosheets whilst enriching the resulting rGO nanosheets with carboxyl functionalities. This "healing" effect observed in rGO-PCA might be of high importance for applications using rGO-PCA matrices and interfaces in particular for electrical devices.

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The ability of metallic nanostructures to support surface plasmon excitations is widely exploited nowadays for developing new technologies and applications in many fields, like communications, medicine or environment. It is known that the plasmonic response of a nanostructure is strongly dependent on its size and shape, and thus a fine control of these features is required for developing applications. In this paper uniaxial colloidal crystal arrays are prepared by convective self-assembly on DVD surfaces. These are then used as template/mask for metal film deposition, in order to obtain two original kinds of metallic nanostructures with controllable morphology: (i) linear arrays of metal half-shells (LAMHSs) and (ii) arrays of periodically serrated plasmonic strips (PSPSs). Angle-resolved optical transmittance measurements reveal the presence of several surface plasmon resonances, while polarized light transmission demonstrates the anisotropic plasmonic response of both LAMHSs and PSPSs. FDTD simulations support the experimental observations and help in the assignments of observed plasmon modes. The proposed linear metallic nanostructures can prove useful for the design of plasmonic components.

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Surface-enhanced Raman scattering (SERS) nano-tags are of increasing interest in biomedical research as viable alternatives to bio-imaging techniques based on semiconductor quantum dots or fluorescent molecules. In this work, we fabricate silica-coated gold nanorods (AuNRs) encoded with two molecular labels to operate as highly effective spectroscopic nano-tags in near-infrared SERS (NIR-SERS) and surface-enhanced resonance Raman scattering combined with metal-enhanced fluorescence (SERRS-MEF), respectively. Specifically, a non-fluorescent molecule with strong affinity for a gold surface (para-aminothiophenol, p-ATP) and a common dye (Nile Blue, NB) with lower affinity have been successfully tested as NIR-SERS nano-tags under laser excitation at 785 nm. Moreover, as a result of designing AuNRs with a plasmon resonance band overlapping the electronic absorption band of the encoded NB molecule, a dual SERRS and MEF performance has been devised under resonant excitation at 633 nm. We explain this result by considering a partial desorption of NB molecules from the metal surface and their trapping into the silica shell at favorable distances to avoid quenching and enhance the fluorescence signal. Finally, we prove that the silica shell prevents the desorption or chemical transformation of p-ATP into p,p'-dimercaptoazobenzene species, as previously noticed, thus providing a highly stable SERRS signal, which is crucial for imaging applications.

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We investigated the effect of the temperature of the plasmonic substrate on the surface enhanced Raman scattering of p-aminothiophenol adsorbed onto a particulate film of gold nanoparticles-decorated polystyrene nanospheres. The results demonstrated that temperature induces important modifications in the overall spectral signature of the charge transfer bands, which are consistent with the generation of a new molecular species. Moreover, the analysis of the shape of the vibrational band at 1078 cm(-1) assigned to the >C-S mode, which is enhanced by electromagnetic mechanism, reveals the co-existence of two distinct bands at 1071 and 1078 cm(-1), assignable to p,p'-dimercaptoazobenzene and p-aminothiophenol, respectively.

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Self-assembled patterns obtained from a drying nanosphere suspension are investigated by computer simulations and simple experiments. Motivated by the earlier experimental results of Sasaki and Hane and Schöpe, we confirm that more ordered triangular lattice structures can be obtained whenever a moderate intensity random shaking is applied on the drying system. Computer simulations are realized on an improved version of a recently elaborated Burridge-Knopoff-type model. Experiments are made following the setup of Sasaki and Hane, using ultrasonic radiation as source for controlled shaking.

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Gold nanostructured films of various thicknesses (15, 30, and 60 nm) are deposited over regular arrays of polystyrene nanospheres in an attempt to evaluate their potential as SERS-active substrates. Atomic force microscopy is used to topographically characterize the substrates as well as to ensure the thickness of the deposited gold films. The optical response of the prepared substrates recommends their use in SERS experiments with multiple laser lines from visible and NIR spectral domains. The assessment of the substrates' SERS activity is performed by using the 532, 633, and 830 nm excitation lines and different average enhancement factor (EF) values are obtained depending on the film thickness and employed laser line. The 60 nm gold nanostructured film generates the greatest local electromagnetic field confinement under NIR excitation and consequently gives rise to maximum SERS enhancement. The large tunability of surface plasmon excitation combined with the advantage of relatively high exhibited average EF values obtained under NIR excitation recommends these substrates as outstanding candidates for upcoming investigations of biological relevant molecules.

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8-Hydroxyquinoline-5-sulfonic acid (HQS) was immobilized onto a strong-base anion-exchange resin AG MP-1 for the purpose of microenvironment investigation, resin characterization, and possibly sensing cadmium. The maximum loading of HQS was found to be 0.9340 mmol/g of AG MP-1. A plateau for Cd complex capacity was already obtained for 0.5500 mmol of HQS/g of AG MP-1. A minicolumn experiment showed an influence of influent Cd concentration on column capacity. IR and Raman spectra proved an electrostatic mode for HQS immobilization and Cd complex formation. UV spectroscopy showed significant differences between solution and solid state for both HQS and Cd complex. A fluorescence microscopy technique was used for fluorescence spectral measurement, microdistribution imaging, and study of photobleaching of HQS and the HQS-Cd complex in the resin phase. The fluorescence of immobilized HQS was found to be red-shifted with regard to the solid-state HQS. The microdistribution of uncomplexed and Cd-complexed AG MP-1-HQS was directly visualized by fluorescence imaging, showing a nonuniform distribution. Cadmium complexation modifies the fluorescence emission of uncomplexed AG MP-1-HQS, exhibiting an increased and red-shifted emission. Significant photobleaching of the fluorescence from the Cd complex was recorded, indicating the occurrence of photochemical reactions within the microenvironment of the resin phase.

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The association of DCF-Na (the salt of the 2-[(2,6-dichlorophenyl)amino]-phenyl-acetic acid) with beta-CD (cyclodextrin) in some therapeutic formulas can contribute to the optimisation of the physico-chemical and pharmaceutical properties of the parent drug. The understanding of the interaction between DCF with beta-CD represents the objective of this study. FT-IR spectroscopy is one of the methods which clarify the nature of these interactions in complexes of such type. Therefore the changes in FT-IR spectra of binary dispersed systems DCF/beta-CD in physical mixture and coprecipitate from methanol (molar ratios: 1/1, 1/2, 2/3, 3/4, 7/4) were analysed. The analysis of the broadening of the X-ray powder diffraction line has been applied to investigate the average effective crystallite size, the mean square of the microstrain caused by distortions within beta-CD crystallite and the fault probability in the binary dispersed DCF/beta-CD coprecipitate system.

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We propose the use of high-index materials for the fabrication of subwavelength diffractive components operating in the visible domain. This approach yields a reduction of fabrication constraints and an improvement of theoretical performance. A blazed grating with subwavelength binary features and with a period of 5.75 wavelengths is designed and fabricated in a TiO(2) layer coated upon a glass substrate. The first-order diffraction efficiency measured with a He-Ne laser beam is 83%, which is slightly larger than that achieved theoretically by the best standard (continuous profile) blazed grating fabricated in glass with the same period.

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We introduce a new structural cutoff beyond which subwavelength gratings cease to behave as homogeneous media and discuss its effects on the proper selection of the sampling periods of subwavelength diffractive elements. According to this analysis, a 3lambda-period blazed binary grating composed of square pillars is designed for He-Ne operation and is fabricated by etching of a TiO>(2) layer deposited upon a glass substrate. Its first-order measured diffraction efficiency is 12% larger than the theoretical efficiency of an ideal blazed échelette grating in glass with the same period.