65 results on '"Lerouge F"'
Search Results
2. Towards adaptive and resilient bioproductive space in Flanders. A spatial and economic analysis. : Naar een adaptieve en veerkrachtige bioproductieve ruimte in Vlaanderen. Een ruimtelijke en economische analyse
- Author
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Lerouge, F, Gulinck, H, and Vranken, L
- Abstract
Within this research, new concepts for spatial planning in Flanders will be developed. More precisely, the capacity of open space to provide various innovative and future-oriented functions and services will be determined. Both agro- and ecosystem services are subjected to economical, social and ecological appraisal, and options for their optimalisation will be studied for different future scenarios. Ultimately, this will be translated to adapted strategies for landscape development and spatial planning. status: published
- Published
- 2019
3. Multimodal imaging with nanoGd reveals spatiotemporal features of neuroinflammation after experimental stroke
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Hubert, V., Hristovska, I., Kárpáti, S., Dey, A., Dumot, C., Amaz, C., Chounlamountri, N., Watrin, C., Comte, J.C., Chauveau, F., Brun, E., Marche, P., Lerouge, F., Parola, S., Berthezène, Y., Vorup-Jensen, T., Pascual, O., and Wiart, M.
- Abstract
The purpose of this study is to propose and validate a preclinical in vivo magnetic resonance imaging (MRI) tool to monitor neuroinflammation following ischemic stroke, based on injection of a novel multimodal nanoprobe, NanoGd, specifically designed for internalization by phagocytic cells. First, it is verified that NanoGd is efficiently internalized by microglia in vitro. In vivo MRI coupled with intravenous injection of NanoGd in a permanent middle cerebral artery occlusion mouse model results in hypointense signals in the ischemic lesion. In these mice, longitudinal two-photon intravital microscopy shows NanoGd internalization by activated CX3CR1-GFP/+ cells. Ex vivo analysis, including phase contrast imaging with synchrotron X-ray, histochemistry, and transmission electron microscopy corroborate NanoGd accumulation within the ischemic lesion and uptake by immune phagocytic cells. Taken together, these results confirm the potential of NanoGd-enhanced MRI as an imaging biomarker of neuroinflammation at the subacute stage of ischemic stroke. As far as it is known, this work is the first to decipher the working mechanism of MR signals induced by a nanoparticle passively targeted at phagocytic cells by performing intravital microscopy back-to-back with MRI. Furthermore, using a gadolinium-based rather than an iron-based contrast agent raises future perspectives for the development of molecular imaging with emerging computed tomography technologies.
- Published
- 2021
4. Highly luminescent YAG:Ce ultra-small nanocrystals, from stable dispersions to thin films
- Author
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Odziomek, M., primary, Chaput, F., additional, Lerouge, F., additional, Sitarz, M., additional, and Parola, S., additional
- Published
- 2017
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5. Two-photon controlled sol–gel condensation for the microfabrication of silica based microstructures. The role of photoacids and photobases
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Kustra, J., primary, Martin, E., additional, Chateau, D., additional, Lerouge, F., additional, Monnereau, C., additional, Andraud, C., additional, Sitarz, M., additional, Baldeck, P. L., additional, and Parola, S., additional
- Published
- 2017
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6. In vivo evaluation of a hybrid nanoparticle for molecular imaging of amyloid aggregation
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Ong, E., Vadcard, F., Verdurand, M., Rositi, H., Peyrin, F., Berthezene, Y., Nighoghossian, N., Lerouge, F., Parola, S., Zimmer, L., Marlene Wiart, Fabien Chauveau, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center (CRNL), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Imagerie Tomographique et Radiothérapie, Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Imagerie et modélisation Vasculaires, Thoraciques et Cérébrales (MOTIVATE), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Centre de recherche en neurosciences de Lyon (CRNL), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Rayet, Béatrice, Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL)
- Subjects
[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging ,[SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging ,[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,[SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] - Abstract
International audience; Amyloid-β (Aβ) fibrillization is described as a central event in the pathogenesis of Alzheimer’s disease (AD). Amyloid imaging is expected to play a pivotal role in early and differential diagnosis of dementias, and in the evaluation of anti-Aβ treatments. Luminescent conjugated oligothiophenes (LCO) have been proposed as optical biomarkers of protein fibrillation [1]. In this paper, we evaluated a fluorescent magnetic hybrid nanoprobe (HNP5011), based on gadolinium fluoride nanoparticles functionalized with luminescent conjugated polythiophenes moieties (Fig. 1). The aim of this study was to investigate its potential for molecular imaging in a rat model bearing intracerebral pre-aggregated Aβ peptides.
- Published
- 2015
7. Dispersion and self-orientation of gold nanoparticles in sol-gel hybrid silica - optical transmission properties
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Lunden, Hampus, Liotta, A., Chateau, D., Lerouge, F., Chaput, F., Parola, S., Brannlund, C., Ghadyani, Z., Kildemo, M., Lindgren, Mikael, Lopes, C., Lunden, Hampus, Liotta, A., Chateau, D., Lerouge, F., Chaput, F., Parola, S., Brannlund, C., Ghadyani, Z., Kildemo, M., Lindgren, Mikael, and Lopes, C.
- Abstract
Silica-based hybrid materials doped with gold nanoparticles (AuNPs) of different shapes were prepared with an adapted sol-gel technology (using MTEOS) and polished to high optical quality. Both spherical (23 and 45 nm in diameter) and bipyramidal (36, 50 and 78 nm in length) AuNPs were prepared and used as dopants. The AuNPs were functionalized with a novel silicone polymer for compatibilization with the sol-gel medium. The glass materials showed well defined localized surface plasmon resonance (SPR) absorbance from the visible to NIR. No redshifts in the spectra, due to the increase in doping concentration, were observed in the glasses, proving that no or very small SPR coupling effects occur. Spectroscopic Muller Matrix Ellipsometry showed that the shorter bipyramidal AuNPs (36 and 50 nm in length) have a clear preferred orientation in the MTEOS matrix, i.e. a tendency to be oriented with their long axis in the plane parallel to the glass surfaces. Dispersions of AuNPs have proven to be good optical power limiters that depend on particle size and geometry. The solid-state glass materials showed good optical power limiting at 532 nm for nanosecond pulses, which did not depend on the size or geometry of the AuNPs. In contrast to the observation at 532 nm, at 600 nm no optical limiting effect was observed. In these solids, as for dispersions of AuNPs, the optical limiting response is caused by scattering., Funding Agencies|Swedish Armed Forces; EOARD [FA8655-12-12106]; AFRL [FA8655-12-12106]
- Published
- 2015
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8. Highly luminescent YAG:Ce ultra-small nanocrystals, from stable dispersions to thin films.
- Author
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Chaput, F., Lerouge, F., Parola, S., Odziomek, M., and Sitarz, M.
- Abstract
The synthesis of well-defined oxide nanocrystals (NCs) with high crystallinity and ultra-small size (typically below 5 nm) is extremely challenging in view of their numerous important related applications. Often the obtained products suffer from particle aggregation, hindering beneficial advantages of nano-size character such as low light scattering properties. Solvothermal methods are very powerful synthetic approaches toward such nanocrystals especially when polyols are used as solvents. Their unique properties and gradual changes in a homologous series of polyols provide a wide range of tools for reaction design. A prominent example of such a reaction is the glycothermal synthesis of Y
3 Al5 O12 (YAG) in 1,4-butanediol in which 20 nm aggregated nanoparticles can be obtained. Herein, we introduce a key evolution of YAG:Ce nanoparticles prepared via a modified glycothermal approach. We emphasize the crucial role of the co-solvent together with the amount of water. Addition of DEG and dehydration of precursors lead to 4 nm non-aggregated nanocrystals with high crystallinity and the correspondingly high photoluminescence emission. Very clear and stable colloidal solutions with concentrations of nanocrystals up to 50% are obtained. The prepared colloids are directly used for the fabrication of homogenous, luminescent and crack-free thin films without the addition of any plasticisers or surfactants. The thickness of the films is simply and efficiently controlled by the concentration of the colloidal solution. [ABSTRACT FROM AUTHOR]- Published
- 2017
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9. Dispersion and self-orientation of gold nanoparticles in sol–gel hybrid silica – optical transmission properties
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Lundén, H., primary, Liotta, A., additional, Chateau, D., additional, Lerouge, F., additional, Chaput, F., additional, Parola, S., additional, Brännlund, C., additional, Ghadyani, Z., additional, Kildemo, M., additional, Lindgren, M., additional, and Lopes, C., additional
- Published
- 2015
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10. From gold nanobipyramids to nanojavelins for a precise tuning of the plasmon resonance to the infrared wavelengths: experimental and theoretical aspects
- Author
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Chateau, D., primary, Liotta, A., additional, Vadcard, F., additional, Navarro, J. R. G., additional, Chaput, F., additional, Lermé, J., additional, Lerouge, F., additional, and Parola, S., additional
- Published
- 2015
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11. Ultrabright and bleaching-resistant hybrid gold nanoparticles for confocal and two-photon fluorecence imaging
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Baldeck, P. L., additional, Navarro, J., additional, Micouin, G., additional, Gabudean, A.-M., additional, Lerouge, F., additional, Monnerau, C., additional, Chaput, F., additional, Andraud, C., additional, and Parola, S., additional
- Published
- 2014
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12. Plasmonic bipyramids for fluorescence enhancement and protection against photobleaching
- Author
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Navarro, J. R. G., primary, Lerouge, F., additional, Micouin, G., additional, Cepraga, C., additional, Favier, A., additional, Charreyre, M. T., additional, Blanchard, N. P., additional, Lermé, J., additional, Chaput, F., additional, Focsan, M., additional, Kamada, K., additional, Baldeck, P. L., additional, and Parola, S., additional
- Published
- 2014
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13. From gold nanoparticles to luminescent nano-objects: experimental aspects for better gold-chromophore interactions
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Navarro Julien R.G. and Lerouge Frederic
- Subjects
gold ,nanoparticles ,plasmon ,fluorescence enhancement ,Physics ,QC1-999 - Abstract
Gold nanoparticles have been the center of interest for scientists since many decades. Within the last 20 years, the research in that field has soared with the possibility to design and study nanoparticles with controlled shapes. From spheres to more complex shapes such as stars, or anisotropic architectures like rods or bipyramids, these new systems feature plasmonic properties making them the tools of choice for studies on light-matter interactions. In that context, fluorescence quenching and enhancement by gold nanostructures is a growing field of research. In this review, we report a non-exhaustive summary of the synthetic modes for various shapes and sizes of isotropic and anisotropic nanoparticles. We then focus on fluorescent studies of these gold nano-objects, either considering “bare” particles (without modifications) or hybrid particles (surface interaction with a chromophore). In the latter case, the well-known metal-enhanced fluorescence (MEF) is more particularly developed; the mechanisms of MEF are discussed in terms of the additional radiative and non-radiative decay rates caused by several parameters such as the vicinity of the chromophore to the metal or the size and shape of the nanostructures.
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- 2017
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14. Ultrabright and bleaching-resistant hybrid gold nanoparticles for confocal and two-photon fluorecence imaging
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Achilefu, Samuel, Raghavachari, Ramesh, Baldeck, P. L., Navarro, J., Micouin, G., Gabudean, A.-M., Lerouge, F., Monnerau, C., Chaput, F., Andraud, C., and Parola, S.
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- 2014
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15. On the origin of controlled anisotropic growth of monodisperse gold nanobipyramids
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Chantal Andraud, Marco Garavelli, Ivan Rivalta, Stephane Parola, Frédéric Lerouge, Marialore Sulpizi, Patrice L. Baldeck, Santosh Kumar Meena, Meena S.K., Lerouge F., Baldeck P., Andraud C., Garavelli M., Parola S., Sulpizi M., and Rivalta I.
- Subjects
Molecular dynamic ,Materials science ,Absorption spectroscopy ,Scanning electron microscope ,Dispersity ,02 engineering and technology ,Surface active agents ,010402 general chemistry ,01 natural sciences ,Molecular dynamics ,chemistry.chemical_compound ,Pulmonary surfactant ,Bromide ,General Materials Science ,chemistry.chemical_classification ,technology, industry, and agriculture ,021001 nanoscience & nanotechnology ,Optical propertie ,0104 chemical sciences ,chemistry ,Chemical engineering ,Anisotropy ,Nanorod ,Gold ,Counterion ,0210 nano-technology ,Scanning electron microscopy ,Micelle - Abstract
We elucidate the crucial role of the cetyl trimethylammonium bromide (CTAB) surfactant in the anisotropic growth mechanism of gold nano-bipyramids, nano-objects with remarkable optical properties and high tunability. Atomistic molecular dynamics simulations predict different surface coverages of the CTAB (positively charged) heads and their (bromide) counterions as function of the gold exposed surfaces. High concentration of CTAB surfactant promotes formation of gold nanograins in solution that work as precursors for the smooth anisotropic growth of more elongated nano-bipyramidal objects. Nanobipyramids feature higher index facets with respect to nanorods, allowing higher CTAB coverages that stabilize their formation and leading to narrower inter-micelles channels that smooth down their anisotropic growth. Absorption spectroscopy and scanning electron microscopy confirmed the formation of nanograins and demonstrated the importance of surfactant concentration on driving the growth towards nano-bipyramids rather than nanorods. The outcome explains the formation of the monodisperse bipyramidal nano-objects, the origin of their controlled shapes and sizes along with their remarkable stability.
- Published
- 2021
16. Simulating Plasmon Resonances of Gold Nanoparticles with Bipyramidal Shapes by Boundary Element Methods
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Stefano Corni, Chantal Andraud, Denis Chateau, Stephane Parola, Frédéric Lerouge, Stefano Baroni, Jacopo Marcheselli, Marco Garavelli, Patrice L. Baldeck, Ivan Rivalta, Marcheselli J., Chateau D., Lerouge F., Baldeck P., Andraud C., Parola S., Baroni S., Corni S., Garavelli M., and Rivalta I.
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Plasmon, computational spectroscopy, nanoparticles ,Materials science ,FOS: Physical sciences ,Physics::Optics ,Nanoparticle ,01 natural sciences ,Molecular physics ,Article ,Settore FIS/03 - Fisica della Materia ,Metal ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Surface plasmon resonance ,Absorption (electromagnetic radiation) ,Boundary element method ,Plasmon ,Condensed Matter - Mesoscale and Nanoscale Physics ,010304 chemical physics ,Computational Physics (physics.comp-ph) ,Computer Science Applications ,Bipyramid ,Colloidal gold ,visual_art ,visual_art.visual_art_medium ,Physics - Computational Physics ,Optics (physics.optics) ,Physics - Optics - Abstract
Computational modeling and accurate simulations of localized surface plasmon resonance (LSPR) absorption properties are reported for gold nanobipyramids (GNBs), a class of metal nanoparticle that features highly tunable, geometrydependent optical properties. GNB bicone models with spherical tips performed best in reproducing experimental LSPR spectra while the comparison with other geometrical models provided a fundamental understanding of base shapes and tip effects on the optical properties of GNBs. Our results demonstrated the importance of averaging all geometrical parameters determined from transmission electron microscopy images to build representative models of GNBs. By assessing the performances of LSPR absorption spectra simulations based on a quasi-static approximation, we provided an applicability range of this approach as a function of the nanoparticle size, paving the way to the theoretical study of the coupling between molecular electron densities and metal nanoparticles in GNB-based nanohybrid systems, with potential applications in the design of nanomaterials for bioimaging, optics and photocatalysis., This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes
- Published
- 2020
17. Surface modification effect on contrast agent efficiency for X-ray based spectral photon-counting scanner/luminescence imaging: from fundamental study to in vivo proof of concept.
- Author
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Cuau L, Akl P, Gautheron A, Houmeau A, Chaput F, Yaromina A, Dubois L, Lambin P, Karpati S, Parola S, Rezaeifar B, Langlois JB, Si-Mohamed SA, Montcel B, Douek P, and Lerouge F
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- Mice, Animals, X-Rays, Luminescence, Mice, Nude, Phantoms, Imaging, Contrast Media, Tomography, X-Ray Computed methods
- Abstract
X-Ray imaging techniques are among the most widely used modalities in medical imaging and their constant evolution has led to the emergence of new technologies. The new generation of computed tomography (CT) systems - spectral photonic counting CT (SPCCT) and X-ray luminescence optical imaging - are examples of such powerful techniques. With these new technologies the rising demand for new contrast agents has led to extensive research in the field of nanoparticles and the possibility to merge the modalities appears to be highly attractive. In this work, we propose the design of lanthanide-based nanocrystals as a multimodal contrast agent with the two aforementioned technologies, allowing SPCCT and optical imaging at the same time. We present a systematic study on the effect of the Tb
3+ doping level and surface modification on the generation of contrast with SPCCT and the luminescence properties of GdF3 :Tb3+ nanocrystals (NCs), comparing different surface grafting with organic ligands and coatings with silica to make these NCs bio-compatible. A comparison of the luminescence properties of these NCs with UV revealed that the best results were obtained for the Gd0.9 Tb0.1 F3 composition. This property was confirmed under X-ray excitation in microCT and with SPCCT. Moreover, we could demonstrate that the intensity of the luminescence and the excited state lifetime are strongly affected by the surface modification. Furthermore, whatever the chemical nature of the ligand, the contrast with SPCCT did not change. Finally, the successful proof of concept of multimodal imaging was performed in vivo with nude mice in the SPCCT taking advantage of the so-called color K-edge imaging method.- Published
- 2024
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18. Gadolinium K-edge angiography with a spectral photon counting CT in atherosclerotic rabbits.
- Author
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Boccalini S, Dessouky R, Rodesch PA, Lacombe H, Yagil Y, Lahoud E, Erhard K, Brendel B, Coulon P, Langlois JB, Chaput F, Parola S, Boussel L, Lerouge F, Si-Mohamed S, and Douek PC
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- Animals, Rabbits, Angiography, Contrast Media, Abdomen, Gadolinium, Tomography, X-Ray Computed methods
- Abstract
Purpose: The purpose of this study was to investigate the feasibility of gadolinium-K-edge-angiography (angio-Gd-K-edge) with gadolinium-based contrast agents (GBCAs) as obtained with spectral photon counting CT (SPCCT) in atherosclerotic rabbits., Materials and Methods: Seven atherosclerotic rabbits underwent angio-SPCCT acquisitions with two GBCAs, with similar intravenous injection protocol. Conventional and angio-Gd-K-edge images were reconstructed with the same parameters. Regions of interest were traced in different locations of the aorta and its branches. Hounsfield unit values, Gd concentrations, signal-to-noise (SNR) and contrast-to-noise (CNR) were calculated and compared. The maximum diameter and the diameter of the aorta in regard to atherosclerotic plaques were measured by two observers. Images were subjectively evaluated regarding vessels' enhancement, artefacts, border sharpness and overall image quality., Results: In the analyzable six rabbits, Gd-K-edge allowed visualization of target vessels and no other structures. HU values and Gd concentrations were greatest in the largest artery (descending aorta, 5.6 ± 0.8 [SD] mm), and lowest in the smallest (renal arteries, 2.1 ± 0.3 mm). While greater for conventional images, CNR and SNR were satisfactory for both images (all P < 0.001). For one observer there were no statistically significant differences in either maximum or plaque-diameters (P = 0.45 and all P > 0.05 in post-hoc analysis, respectively). For the second observer, there were no significant differences for images reconstructed with the same parameters (all P < 0.05). All subjective criteria scored higher for conventional images compared to K-edge (all P < 0.01), with the highest scores for enhancement (4.3-4.4 vs. 3.1-3.4)., Conclusion: With SPCCT, angio-Gd-K-edge after injection of GBCAs in atherosclerotic rabbits is feasible and allows for angiography-like visualization of small arteries and for the reliable measurement of their diameters., Competing Interests: Declaration of Competing Interest Yoad Yagil PhD, Elias Lahoud PhD, Klaus Erhard PhD, Bernhard Brendel PhD and Philippe Coulon PhD are employees of Philips Healthcare., (Copyright © 2023. Published by Elsevier Masson SAS.)
- Published
- 2023
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19. Quantum-Classical Protocol for Efficient Characterization of Absorption Lineshape and Fluorescence Quenching upon Aggregation: The Case of Zinc Phthalocyanine Dyes.
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Aarabi M, Aranda D, Gholami S, Meena SK, Lerouge F, Bretonniere Y, Gürol I, Baldeck P, Parola S, Dumoulin F, Cerezo J, Garavelli M, Santoro F, and Rivalta I
- Abstract
A quantum-classical protocol that incorporates Jahn-Teller vibronic coupling effects and cluster analysis of molecular dynamics simulations is reported, providing a tool for simulations of absorption spectra and ultrafast nonadiabatic dynamics in large molecular photosystems undergoing aggregation in solution. Employing zinc phthalocyanine dyes as target systems, we demonstrated that the proposed protocol provided fundamental information on vibronic, electronic couplings and thermal dynamical effects that mostly contribute to the absorption spectra lineshape and the fluorescence quenching processes upon dye aggregation. Decomposing the various effects arising upon dimer formation, the structure-property relations associated with their optical responses have been deciphered at atomistic resolution.
- Published
- 2023
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20. Ultra-Small YPO 4 -YAG:Ce Composite Nanophosphors with a Photoluminescence Quantum Yield Exceeding 50.
- Author
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Yan Y, Mesbah A, Khrouz L, Bouillet C, Lorentz C, Blanchard N, Berends AC, Anne van de Haar M, Lerouge F, Krames MR, Ersen O, Chaput F, and Parola S
- Abstract
Synthesis of high quality colloidal Cerium(III) doped yttrium aluminum garnet (Y
3 Al5 O12 :Ce3+ , "YAG:Ce") nanoparticles (NPs) meeting simultaneously both ultra-small size and high photoluminescence (PL) performance is challenging, as generally a particle size/PL trade-off has been observed for this type of nanomaterials. The glycothermal route is capable to yield ultra-fine crystalline colloidal YAG:Ce nanoparticles with a particle size as small as 10 nm but with quantum yield (QY) no more than 20%. In this paper, the first ultra-small YPO4 -YAG:Ce nanocomposite phosphor particles having an exceptional QY-to-size performance with an QY up to 53% while maintaining the particle size ≈10 nm is reported. The NPs are produced via a phosphoric acid- and extra yttrium acetate-assisted glycothermal synthesis route. Localization of phosphate and extra yttrium entities with respect to cerium centers in the YAG host has been determined by fine structural analysis techniques such as X-ray diffration (XRD), solid state nuclear magnetic resonance (NMR), and high resolution scanning transmission electron microscopy (HR-STEM), and shows distinct YPO4 and YAG phases. Finally, a correlation between the additive-induced physico-chemical environment change around cerium centers and the increasing PL performance has been suggested based on electron paramagnetic resonance (EPR), X-ray photoelectron spectrometry (XPS) data, and crystallographic simulation studies., (© 2023 The Authors. Small published by Wiley-VCH GmbH.)- Published
- 2023
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21. Use of metal-based contrast agents for in vivo MR and CT imaging of phagocytic cells in neurological pathologies.
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Wiart M, Tavakoli C, Hubert V, Hristovska I, Dumot C, Parola S, Lerouge F, Chauveau F, Canet-Soulas E, Pascual O, Cormode DP, Brun E, and Elleaume H
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- Humans, Magnetic Resonance Imaging methods, Tomography, X-Ray Computed, Gadolinium, Phagocytes, Contrast Media, Nervous System Diseases diagnostic imaging
- Abstract
The activation of phagocytic cells is a hallmark of many neurological diseases. Imaging them in their 3-dimensional cerebral environment over time is crucial to better understand their role in disease pathogenesis and to monitor their potential therapeutic effects. Phagocytic cells have the ability to internalize metal-based contrast agents both in vitro and in vivo and can thus be tracked by magnetic resonance imaging (MRI) or computed tomography (CT). In this review article, we summarize the different labelling strategies, contrast agents, and in vivo imaging modalities that can be used to monitor cells with phagocytic activity in the central nervous system using MRI and CT, with a focus on clinical applications. Metal-based nanoparticle contrast agents such as gadolinium, gold and iron are ideal candidates for these applications as they have favourable magnetic and/or radiopaque properties and can be fine-tuned for optimal uptake by phagocytic cells. However, they also come with downsides due to their potential toxicity, especially in the brain where they might accumulate. We therefore conclude our review by discussing the pitfalls, safety and potential for clinical translation of these metal-based neuroimaging techniques. Early results in patients with neuropathologies such as multiple sclerosis, stroke, trauma, cerebral aneurysm and glioblastoma are promising. If the challenges represented by safety issues are overcome, phagocytic cells imaging will be a very valuable tool for studying and understanding the inflammatory response and evaluating treatments that aim at mitigating this response in patients with neurological diseases., Competing Interests: Declaration of Competing Interest The authors have no conflict of interests to declare., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2023
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22. In vivo targeting and multimodal imaging of cerebral amyloid-β aggregates using hybrid GdF 3 nanoparticles.
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Lerouge F, Ong E, Rositi H, Mpambani F, Berner LP, Bolbos R, Olivier C, Peyrin F, Apputukan VK, Monnereau C, Andraud C, Chaput F, Berthezène Y, Braun B, Jucker M, Åslund AK, Nyström S, Hammarström P, R Nilsson KP, Lindgren M, Wiart M, Chauveau F, and Parola S
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- Mice, Rats, Animals, Tissue Distribution, Amyloid beta-Peptides metabolism, Mice, Transgenic, Brain diagnostic imaging, Brain metabolism, Multimodal Imaging, Disease Models, Animal, Alzheimer Disease diagnostic imaging, Nanoparticles
- Abstract
Aim: To propose a new multimodal imaging agent targeting amyloid-β (Aβ) plaques in Alzheimer's disease. Materials & methods: A new generation of hybrid contrast agents, based on gadolinium fluoride nanoparticles grafted with a pentameric luminescent-conjugated polythiophene, was designed, extensively characterized and evaluated in animal models of Alzheimer's disease through MRI, two-photon microscopy and synchrotron x-ray phase-contrast imaging. Results & conclusion: Two different grafting densities of luminescent-conjugated polythiophene were achieved while preserving colloidal stability and fluorescent properties, and without affecting biodistribution. In vivo brain uptake was dependent on the blood-brain barrier status. Nevertheless, multimodal imaging showed successful Aβ targeting in both transgenic mice and Aβ fibril-injected rats.
- Published
- 2022
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23. On the origin of controlled anisotropic growth of monodisperse gold nanobipyramids.
- Author
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Meena SK, Lerouge F, Baldeck P, Andraud C, Garavelli M, Parola S, Sulpizi M, and Rivalta I
- Abstract
We elucidate the crucial role of the cetyl trimethylammonium bromide (CTAB) surfactant in the anisotropic growth mechanism of gold nano-bipyramids, nano-objects with remarkable optical properties and high tunability. Atomistic molecular dynamics simulations predict different surface coverages of the CTAB (positively charged) heads and their (bromide) counterions as function of the gold exposed surfaces. High concentration of CTAB surfactant promotes formation of gold nanograins in solution that work as precursors for the smooth anisotropic growth of more elongated nano-bipyramidal objects. Nanobipyramids feature higher index facets with respect to nanorods, allowing higher CTAB coverages that stabilize their formation and leading to narrower inter-micelles channels that smooth down their anisotropic growth. Absorption spectroscopy and scanning electron microscopy confirmed the formation of nanograins and demonstrated the importance of surfactant concentration on driving the growth towards nano-bipyramids rather than nanorods. The outcome explains the formation of the monodisperse bipyramidal nano-objects, the origin of their controlled shapes and sizes along with their remarkable stability.
- Published
- 2021
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24. Rare-earth doped micro-emitters made by lift-off processing in pulsed laser deposited layers on Si substrate.
- Author
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Gassenq A, Cleyet-Merle E, Sahib H, Baguenard B, Belarouci A, Orobtchouk R, Lerouge F, Guy S, and Pereira A
- Abstract
Rare earth emitters are promising in integrated optics but require complex integration on silicon. In this work, we have fabricated an Y
2 O3 :Eu3+ micro-emitter on SiO2 on Si substrate without etching. Since pulsed laser deposition produces a high quality layer at room temperature, material can be locally deposited on top of substrates by lift-off processing. After annealing, microstructures exhibit good crystallographic quality with controlled dimensions for light confinement and narrow emission. This works allows envisioning rare-earth doped micro-photonic structures directly integrated on silicon without etching, which opens the way to integration of new functional materials on silicon platform.- Published
- 2021
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25. Hybrid multimodal contrast agent for multiscale in vivo investigation of neuroinflammation.
- Author
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Karpati S, Hubert V, Hristovska I, Lerouge F, Chaput F, Bretonnière Y, Andraud C, Banyasz A, Micouin G, Monteil M, Lecouvey M, Mercey-Ressejac M, Dey AK, Marche PN, Lindgren M, Pascual O, Wiart M, and Parola S
- Subjects
- Animals, Magnetic Resonance Imaging, Multimodal Imaging, Polyethylene Glycols, Contrast Media, Gadolinium
- Abstract
Neuroinflammation is a process common to several brain pathologies. Despites its medical relevance, it still remains poorly understood; there is therefore a need to develop new in vivo preclinical imaging strategies to monitor inflammatory processes longitudinally. We here present the development of a hybrid imaging nanoprobe named NP3, that was specifically designed to get internalized by phagocytic cells and imaged in vivo with MRI and bi-photon microscopy. NP3 is composed of a 16 nm core of gadolinium fluoride (GdF3), coated with bisphosphonate polyethylene glycol (PEG) and functionalized with a Lemke-type fluorophore. It has a hydrodynamic diameter of 28 ± 8 nm and a zeta potential of -42 ± 6 mV. The MR relaxivity ratio at 7 T is r1/r2 = 20; therefore, NP3 is well suited as a T2/T2* contrast agent. In vitro cytotoxicity assessments performed on four human cell lines revealed no toxic effects of NP3. In addition, NP3 is internalized by macrophages in vitro without inducing inflammation or cytotoxicity. In vivo, uptake of NP3 has been observed in the spleen and the liver. NP3 has a prolonged vascular remanence, which is an advantage for macrophage uptake in vivo. The proof-of-concept that NP3 may be used as a contrast agent targeting phagocytic cells is provided in an animal model of ischemic stroke in transgenic CX3CR1-GFP/+ mice using three complementary imaging modalities: MRI, intravital two-photon microscopy and phase contrast imaging with synchrotron X-rays. In summary, NP3 is a promising preclinical tool for the multiscale and multimodal investigation of neuroinflammation.
- Published
- 2021
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26. Single Gold Bipyramid Nanoparticle Orientation Measured by Plasmon-Resonant Scattering Polarimetry.
- Author
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Vu NC, Ouzit Z, Lethiec C, Maître A, Coolen L, Lerouge F, and Laverdant J
- Abstract
The 3D orientation of a single gold nanoparticle is probed experimentally by light scattering polarimetry. We choose high-quality gold bipyramids (AuBPs) that support around 700 nm a well-defined narrow longitudinal localized surface plasmonic resonance (LSPR) which can be considered as a linear radiating dipole. A specific spectroscopic dark-field technique was used to control the collection angles of the scattered light. The in-plane as well as the out-of-plane angles are determined by analyzing the polarization of the scattered radiation. The data are compared with a previously developed model where the environment and the angular collection both play crucial roles. We show that most of the single AuBPs present an out-of-plane orientation consistent with their geometry. Finally, the fundamental role of the collection angles on the determination of the orientation is investigated for the first time. Several features are then deduced: we validate the choice of the analytical 1D model, an accurate 3D orientation is obtained, and the critical contribution of the evanescent waves is highlighted.
- Published
- 2021
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27. ICG-loaded gold nano-bipyramids with NIR activatable dual PTT-PDT therapeutic potential in melanoma cells.
- Author
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Campu A, Focsan M, Lerouge F, Borlan R, Tie L, Rugina D, and Astilean S
- Subjects
- Gold, Humans, Indocyanine Green, Melanoma, Photochemotherapy
- Abstract
A great amount of effort is directed towards the progress of cancer treatment approaches aspiring to develop non-invasive, targeted and highly efficient therapies. In this context, Photothermal (PTT) and Photodynamic (PDT) Therapies were proven as promising. This work aims to integrate the therapeutic activities of two near-infrared (NIR) photoactive biomaterials - gold nano-bipyramids (AuBPs) and Indocyanine Green (ICG) - into one single targeted hybrid nanosystem able to operate as dual PTT-PDT agent with higher efficiency compared with each one alone. Firstly, different aspect ratio' AuBPs were systematically investigated in water solution for their intrinsic ability to efficiently generate toxic reactive oxygen species, namely oxygen singlet (
1 O2 ), under NIR laser irradiation, as this effect is less investigated in literature. Interestingly, the photodynamic activity of AuBPs measured by monitoring the photooxidation of 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) - a well-known1 O2 sensor, is important, counting for 30 % decrease in ABDA optical absorbance for the most active AuBPs, well-correlating with the previously determined photothermal conversion efficiency. Furthermore, ICG was successfully grafted onto the Poly-lactic acid (PLA) coating of plasmonic nanoparticles and, consequently, the as-designed fully integrated hybrid nanosystem shows improved PTT-PDT performance in solution. Specifically, by triggering simultaneous PTT-PDT activities, the1 O2 amount is doubled, while the heating monitoring shows higher and faster increase in temperature compared to AuBPs alone. Finally, the efficiency of the combined PTT-PDT therapeutic activity was validated in vitro against B16-F10 cell line by covalent conjugation of the nanosystem with Folic Acid, which ensures the cellular recognition by overexpression of folate receptor., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)- Published
- 2020
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28. Au nanobipyramids@mSiO 2 core-shell nanoparticles for plasmon-enhanced singlet oxygen photooxygenations in segmented flow microreactors.
- Author
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Mendoza C, Désert A, Chateau D, Monnereau C, Khrouz L, Lerouge F, Andraud C, Monbaliu JM, Parola S, and Heinrichs B
- Abstract
The plasmonic features of gold nanomaterials provide intriguing optical effects which can find potential applications in various fields. These effects depend strongly on the size and shape of the metal nanostructures. For instance, Au bipyramids (AuBPs) exhibit intense and well-defined plasmon resonance, easily tunable by controlling their aspect ratio, which can act synergistically with chromophores for enhancing their photophysical properties. In Rose Bengal-nanoparticle systems it is now well established that the control of the dye-to-nanoparticle distance ranging from 10 to 20 nm as well as spectral overlaps is crucial to achieve appropriate coupling between the plasmon resonance and the dye, thus affecting its ability to generate singlet oxygen (
1 O2 ). We have developed AuBPs@mSiO2 core-shell nanostructures that provide control over the distance between the metal surface and the photosensitizers for improving the production of1 O2 (metal-enhanced1 O2 production - ME1 O2 ). A drastic enhancement of1 O2 generation is evidenced for the resulting AuBPs and AuBPs@mSiO2 in the presence of Rose Bengal, using a combination of three indirect methods of1 O2 detection, namely in operando Electron Paramagnetic Resonance (EPR) with 2,2,6,6-tetramethylpiperidine (TEMP) as a chemical trap, photooxygenation of the fluorescence probe anthracene-9,10-dipropionic acid (ADPA), and photooxygenation of methionine to methionine sulfoxide in a segmented flow microreactor., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2020
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29. Radiation Dose-Enhancement Is a Potent Radiotherapeutic Effect of Rare-Earth Composite Nanoscintillators in Preclinical Models of Glioblastoma.
- Author
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Bulin AL, Broekgaarden M, Chaput F, Baisamy V, Garrevoet J, Busser B, Brueckner D, Youssef A, Ravanat JL, Dujardin C, Motto-Ros V, Lerouge F, Bohic S, Sancey L, and Elleaume H
- Abstract
To improve the prognosis of glioblastoma, innovative radiotherapy regimens are required to augment the effect of tolerable radiation doses while sparing surrounding tissues. In this context, nanoscintillators are emerging radiotherapeutics that down-convert X-rays into photons with energies ranging from UV to near-infrared. During radiotherapy, these scintillating properties amplify radiation-induced damage by UV-C emission or photodynamic effects. Additionally, nanoscintillators that contain high-Z elements are likely to induce another, currently unexplored effect: radiation dose-enhancement. This phenomenon stems from a higher photoelectric absorption of orthovoltage X-rays by high-Z elements compared to tissues, resulting in increased production of tissue-damaging photo- and Auger electrons. In this study, Geant4 simulations reveal that rare-earth composite LaF
3 :Ce nanoscintillators effectively generate photo- and Auger-electrons upon orthovoltage X-rays. 3D spatially resolved X-ray fluorescence microtomography shows that LaF3 :Ce highly concentrates in microtumors and enhances radiotherapy in an X-ray energy-dependent manner. In an aggressive syngeneic model of orthotopic glioblastoma, intracerebral injection of LaF3 :Ce is well tolerated and achieves complete tumor remission in 15% of the subjects receiving monochromatic synchrotron radiotherapy. This study provides unequivocal evidence for radiation dose-enhancement by nanoscintillators, eliciting a prominent radiotherapeutic effect. Altogether, nanoscintillators have invaluable properties for enhancing the focal damage of radiotherapy in glioblastoma and other radioresistant cancers., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Published by Wiley‐VCH GmbH.)- Published
- 2020
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30. Microfluidic platform for integrated plasmonic detection in laminal flow.
- Author
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Campu A, Lerouge F, Craciun AM, Murariu T, Turcu I, Astilean S, and Monica F
- Abstract
In this work, we propose a novel approach to design robust microfluidic devices with integrated plasmonic transducers allowing portability, reduced analysis time through dynamic measurements and high sensitivity. Specifically, the strategy we apply involves two steps: (i) the controlled deposition of gold bipyramidal nanoparticles (AuBPs) onto a functionalized solid glass substrate and (ii) the integration of the as-fabricated plasmonic substrate into a polydimethylsiloxane (PDMS) microfluidic circuit. The localized surface plasmon resonance (LSPR) sensitivity of the plasmonic-microfluidic device was evaluated by monitoring the optical responses at refractive index changes, proving a bulk sensitivity of 243 nm RIU
-1 for the longitudinal LSPR band of isolated AuBPs and 150 nm RIU-1 for the band assigned to end-to-end linked nanoparticles. A strong electric field generated in the gaps between AuBPs-due to the generation of the so-called extrinsic 'hot-spots'-was subsequently proved by the volumetric surface enhanced Raman scattering (SERS) detection of molecules in continuous flow conditions by loading the analyte into the microfluidic channel via a syringe pump. In conclusion, our miniaturized portable microfluidic system aims to detect and identify, in real-time with high accuracy, analyte molecules in laminal flow, thus providing a groundwork for further complex biosensing applications.- Published
- 2020
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31. Simulating Plasmon Resonances of Gold Nanoparticles with Bipyramidal Shapes by Boundary Element Methods.
- Author
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Marcheselli J, Chateau D, Lerouge F, Baldeck P, Andraud C, Parola S, Baroni S, Corni S, Garavelli M, and Rivalta I
- Abstract
Computational modeling and accurate simulations of localized surface plasmon resonance (LSPR) absorption properties are reported for gold nanobipyramids (GNBs), a class of metal nanoparticle that features highly tunable, geometry-dependent optical properties. GNB bicone models with spherical tips performed best in reproducing experimental LSPR spectra while the comparison with other geometrical models provided a fundamental understanding of base shapes and tip effects on the optical properties of GNBs. Our results demonstrated the importance of averaging all geometrical parameters determined from transmission electron microscopy images to build representative models of GNBs. By assessing the performances of LSPR absorption spectra simulations based on a quasi-static approximation, we provided an applicability range of this approach as a function of the nanoparticle size, paving the way to the theoretical study of the coupling between molecular electron densities and metal nanoparticles in GNB-based nanohybrid systems, with potential applications in the design of nanomaterials for bioimaging, optics and photocatalysis.
- Published
- 2020
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32. Liquid-Crystalline Suspensions of Photosensitive Paramagnetic CeF 3 Nanodiscs.
- Author
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Chaput F, Lerouge F, Bulin AL, Amans D, Odziomek M, Faure AC, Monteil M, Dozov I, Parola S, Bouquet F, Lecouvey M, Davidson P, and Dujardin C
- Abstract
The design of high-performance energy-converting materials is an essential step for the development of sensors, but the production of the bulk materials currently used remains costly and difficult. Therefore, a different approach based on the self-assembly of nanoparticles has been explored. We report on the preparation by solvothermal synthesis of highly crystalline CeF
3 nanodiscs. Their surface modification by bisphosphonate ligands led to stable, highly concentrated, colloidal suspensions in water. Despite the low aspect ratio of the nanodiscs (∼6), a liquid-crystalline nematic phase spontaneously appeared in these colloidal suspensions. Thanks to the paramagnetic character of the nanodiscs, the nematic phase was easily aligned by a weak (0.5 T) magnetic field, which provides a simple and convenient way of orienting all of the nanodiscs in suspension in the same direction. Moreover, the more dilute, isotropic, suspensions displayed strong (electric and magnetic) field-induced orientation of the nanodiscs (Kerr and Cotton-Mouton effects), with fast enough response times to make them suitable for use in electro-optic devices. Furthermore, an emission study showed a direct relation between the luminescence intensity and magnetic-field-induced orientation of the colloids. Finally, with their fast radiative recombination decay rates, the nanodiscs show luminescence properties that compare quite favorably with those of bulk CeF3 . Therefore, these CeF3 nanodiscs are very promising building blocks for the development and processing of photosensitive materials for sensor applications.- Published
- 2019
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33. Beyond the Concentration Limitation in the Synthesis of Nanobipyramids and Other Pentatwinned Gold Nanostructures.
- Author
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Chateau D, Desert A, Lerouge F, Landaburu G, Santucci S, and Parola S
- Abstract
Gold nanoparticles offer unique optoelectronic properties relevant for a wide range of processes and products, in biology and medicine (therapeutic agents, diagnostic, drug delivery), as well as in electronics, photovoltaics, and catalysis. So far, various synthesis methods proposed have led to rather limited concentration and purity of the colloidal suspensions, severely hindering their use. Here, we present a simple and versatile procedure for the synthesis of gold pentatwinned nanostructures, including nanobipyramids based on a seed-mediated growth process that overcomes the concentration limitations of current methods by 2 orders of magnitude. Moreover, our novel process offers quantitative yields while easily allowing a fine control of the particles' shape, size (with a high monodispersity), and plasmonic properties. Finally, we demonstrate that our method can be easily upscaled to produce large amounts of nanostructures, up to the gram scale, with minimal waste and postprocessing, thus facilitating their use for further applications and industrial developments.
- Published
- 2019
- Full Text
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34. Hybrid Nano-GdF 3 contrast media allows pre-clinical in vivo element-specific K-edge imaging and quantification.
- Author
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Halttunen N, Lerouge F, Chaput F, Vandamme M, Karpati S, Si-Mohamed S, Sigovan M, Boussel L, Chereul E, Douek P, and Parola S
- Subjects
- Animals, Contrast Media chemistry, Growth Differentiation Factor 3 pharmacology, Humans, Iodine chemistry, Iodine pharmacology, Magnetic Resonance Imaging, Mice, Phantoms, Imaging, Photons therapeutic use, Contrast Media pharmacology, Nanoparticles chemistry, Tomography, X-Ray Computed methods
- Abstract
Computed tomography (CT) is a widely used imaging modality. Among the recent technical improvements to increase the range of detection for optimized diagnostic, new devices such as dual energy CT allow elemental discrimination but still remain limited to two energies. Spectral photon-counting CT (SPCCT) is an emerging X-ray imaging technology with a completely new multiple energy detection and high spatial resolution (200 μm). This unique technique allows detection and quantification of a given element thanks to an element-specific increase in X-ray absorption for an energy (K-band) depending on its atomic number. The main contrast media used hitherto are iodine-based compounds but the K-edge of iodine (33.2 keV) is out of the range of detection. Therefore, it is crucial to develop contrast media suitable for this advanced technology. Gadolinium, well known and used element for MRI, possess a K-edge (50.2 keV) well suited for the SPCCT modality. The use of nano-objects instead of molecular entities is pushed by the necessity of high local concentration. In this work, nano-GdF
3 is validated on a clinical based prototype, to be used as efficient in vivo contrast media. Beside an extremely high stability, it presents long lasting time in the blood pool allowing perfusion imaging of small animals, without apparent toxicity.- Published
- 2019
- Full Text
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35. Design and Application of High Optical Quality YAG:Ce Nanocrystal-Loaded Silica Aerogels.
- Author
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Odziomek M, Chaput F, Dujardin C, Lerouge F, Cassette P, Sitarz M, and Parola S
- Abstract
The intrinsic properties of silica aerogels make them well suited for applications requiring high surface area. Therefore, the dispersion of functional nanoparticles (NPs) in these highly porous structures gives access to materials for wide range of applications such as catalysis, energy storage or sensing. The last one is particularly interesting if such composites possess good optical quality. Herein, the synthesis of monolithic and transparent silica aerogels highly loaded with Y
3 Al5 O12 :Ce nanocrystals (NCs) (up to 50 wt %) is reported. The developed composite aerogels can be impregnated with liquids, contrary to most of existing aerogels, which crack because of the strong capillary forces. Therefore, this system is designed as a novel concept of 3D porous scintillator, using the efficient photoluminescent and scintillating properties of Y3 Al5 O12 :Ce. The investigated fluid containing low-energetic ionizing radiation emitters impregnates the material, which assures the efficient harvesting of radiation because of highly developed surface area. Such composites prove to be efficient new-type detectors of low-energy beta radiation both in liquids and gases.- Published
- 2018
- Full Text
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36. Single gold bipyramids on a silanized substrate as robust plasmonic sensors for liquid environments.
- Author
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Rye JM, Bonnet C, Lerouge F, Pellarin M, Lermé J, Parola S, and Cottancin E
- Abstract
Sensitive, robust and stable sensors are required to bring biosensing techniques from the forefront of research to clinical and commercial settings. To this end, we report on the development of new robust plasmonic sensors consisting of gold nano-bipyramids (BPs) grafted to a glass substrate via silanization, associated with a novel setup based on Spatial Modulation Spectroscopy allowing the measurement of the optical response of individual nano-objects in a liquid environment. We thereby show that changes in the refractive index of the medium around individual silanized BPs can be detected by measuring their plasmonic shift with sensitivities comparable to values reported elsewhere and in good agreement with theoretical calculations. The optical response is furthermore shown to be stable and robust allowing for repeated measurements in different media and storage over many months. This work opens up new perspectives in the field of plasmonic bio-sensing as our setup is readily adaptable to dynamic liquid measurements and a wide range of applications such as the detection of clinically important analytes or pollutants in water.
- Published
- 2018
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37. Two-Photon Fluorescence and Magnetic Resonance Specific Imaging of Aβ Amyloid Using Hybrid Nano-GdF 3 Contrast Media.
- Author
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Mpambani F, Åslund AKO, Lerouge F, Nyström S, Reitan N, Huuse EM, Widerøe M, Chaput F, Monnereau C, Andraud C, Lecouvey M, Handrick S, Prokop S, Heppner FL, Nilsson P, Hammarström P, Lindgren M, and Parola S
- Abstract
Real time in vivo detection of Amyloid β (Aβ) deposits at an early stage may lead to faster and more conclusive diagnosis of Alzheimer's disease (AD) and can facilitate the follow up of the effect of therapeutic interventions. In this work, the capability of new hybrid nanomaterials to target and detect Aβ aggregates using magnetic resonance (MRI) and fluorescence imaging is demonstrated. These smart contrast agents contain paramagnetic nanoparticles surrounded by luminescent conjugated oligothiophenes (LCOs) known to selectively bind to Aβ aggregates, with emission spectra strongly dependent on their conformations, opening the possibilities for several fluorescence imaging modes for AD diagnostics. Relaxivity is evaluated in vitro and ex vivo . The capability of these contrast media to link to Aβ fibrils in stained sections is revealed using transmission electron microscopy and fluorescence microscopy. Preliminary in vivo experiments show the ability of the contrast agent to diffuse through the blood-brain barrier of model animals and specifically stain amyloid deposits.
- Published
- 2018
- Full Text
- View/download PDF
38. Gold NanoBipyramids Performing as Highly Sensitive Dual-Modal Optical Immunosensors.
- Author
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Campu A, Lerouge F, Chateau D, Chaput F, Baldeck P, Parola S, Maniu D, Craciun AM, Vulpoi A, Astilean S, and Focsan M
- Subjects
- Biotin chemistry, Humans, Streptavidin chemistry, Biosensing Techniques instrumentation, Gold chemistry, Immunoassay instrumentation, Immunoglobulin G analysis, Spectrum Analysis, Raman instrumentation, Surface Plasmon Resonance instrumentation
- Abstract
In this work, we demonstrate the feasibility of gold bipyramidal-shaped nanoparticles (AuBPs) to be used as active plasmonic nanoplatforms for the detection of the biotin-streptavidin interaction in aqueous solution via both Localized Surface Plasmon Resonance and Surface Enhanced Raman Scattering (LSPR/SERS). Our proof of concept exploits the precise attachment of the recognition element at the tips of AuBPs, where the electromagnetic field is stronger, which is beneficial to the surface sensitivity of longitudinal LSPR on the local refractive index and to the electromagnetic enhancement of SERS activity, too. Indeed, successive red shifts of the longitudinal LSPR associated with increased local refractive index reveal the attachment of para-aminothiophenol (p-ATP) chemically labeled Biotin to the Au surface and the specific capture of the target protein by biotin-functionalized AuBPs. Finite-Difference Time-Domain simulations based on the reconstructed index of refraction confirm LSPR measurements. However, the molecular identification of the biotin-streptavidin interaction remains elusive by LSPR investigation alone. Remarkably, we succeeded to complement the LSPR detection with reliable SERS measurements which permitted to (a) certify the molecular identification of biotin-streptavidin interaction and (b) extend the limit of detection of streptavidin in solution toward 10
-12 M. Finally, to further probe the possibility to implement the AuBPs as dual LSPR-SERS based immunoassays in solution for real clinical diagnostics, we additionally investigated the AuBP's performance to transduce the specific antihuman IgG- human IgG binding event, providing thus a reference design for building unique plasmonic immunoassays for dual-optical detection of target proteins in aqueous solution.- Published
- 2018
- Full Text
- View/download PDF
39. Hierarchically structured lithium titanate for ultrafast charging in long-life high capacity batteries.
- Author
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Odziomek M, Chaput F, Rutkowska A, Świerczek K, Olszewska D, Sitarz M, Lerouge F, and Parola S
- Abstract
High-performance Li-ion batteries require materials with well-designed and controlled structures on nanometre and micrometre scales. Electrochemical properties can be enhanced by reducing crystallite size and by manipulating structure and morphology. Here we show a method for preparing hierarchically structured Li
4 Ti5 O12 yielding nano- and microstructure well-suited for use in lithium-ion batteries. Scalable glycothermal synthesis yields well-crystallized primary 4-8 nm nanoparticles, assembled into porous secondary particles. X-ray photoelectron spectroscopy reveals presence of Ti+4 only; combined with chemical analysis showing lithium deficiency, this suggests oxygen non-stoichiometry. Electron microscopy confirms hierarchical morphology of the obtained material. Extended cycling tests in half cells demonstrates capacity of 170 mAh g-1 and no sign of capacity fading after 1,000 cycles at 50C rate (charging completed in 72 s). The particular combination of nanostructure, microstructure and non-stoichiometry for the prepared lithium titanate is believed to underlie the observed electrochemical performance of material.- Published
- 2017
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40. WO3 nanorods created by self-assembly of highly crystalline nanowires under hydrothermal conditions.
- Author
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Navarro JR, Mayence A, Andrade J, Lerouge F, Chaput F, Oleynikov P, Bergström L, Parola S, and Pawlicka A
- Abstract
WO3 nanorods and wires were obtained via hydrothermal synthesis using sodium tungstate as a precursor and either oxalic acid, citric acid, or poly(methacrylic acid) as a stabilizing agent. Transmission electron microscopy images showed that the organic acids with different numbers of carboxylic groups per molecule influence the final sizes and stacking nanostructures of WO3 wires. Three-dimensional electron diffraction tomography of a single nanocrystal revealed a hexagonal WO3 structure with preferential growth along the c-axis, which was confirmed by high-resolution transmission electron microscopy. WO3 nanowires were also spin-coated onto an indium tin oxide/glass conducting substrate, resulting in the formation of a film that was characterized by scanning electron microscopy. Finally, cyclic voltammetry measurements performed on the WO3 thin film showed voltammograms typical for the WO3 redox process.
- Published
- 2014
- Full Text
- View/download PDF
41. Nanocarriers with ultrahigh chromophore loading for fluorescence bio-imaging and photodynamic therapy.
- Author
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Navarro JR, Lerouge F, Cepraga C, Micouin G, Favier A, Chateau D, Charreyre MT, Lanoë PH, Monnereau C, Chaput F, Marotte S, Leverrier Y, Marvel J, Kamada K, Andraud C, Baldeck PL, and Parola S
- Subjects
- Cell Line, Tumor, Humans, Molecular Structure, Fluorescence, Gold chemistry, Nanoparticles chemistry, Optical Imaging methods, Photochemotherapy methods
- Abstract
We describe the design of original nanocarriers that allows for ultrahigh chromophore loading while maintaining the photo-activity of each individual molecule. They consist in shells of charged biocompatible polymers grafted on gold nanospheres. The self-organization of extended polymer chains results from repulsive charges and steric interactions that are optimized by tuning the surface curvature of nanoparticles. This type of nano-scaffolds can be used as light-activated theranostic agents for fluorescence imaging and photodynamic therapy. We demonstrate that, labeled with a fluorescent photosensitizer, it can localize therapeutic molecules before triggering the cell death of B16-F10 melanoma with an efficiency that is similar to the efficiency of the polymer conjugate alone, and with the advantage of extremely high local loading of photosensitizers (object concentration in the picomolar range)., (© 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
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42. Tuning dye-to-particle interactions toward luminescent gold nanostars.
- Author
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Navarro JR, Liotta A, Faure AC, Lerouge F, Chaput F, Micouin G, Baldeck PL, and Parola S
- Subjects
- Coloring Agents chemistry, Gold chemistry, Metal Nanoparticles chemistry
- Abstract
Light-matter interactions are of great interest for potential biological applications (bioimaging, biosensing, phototherapy). For such applications, sharp nanostructures exhibit interesting features since their extinction bands (surface plasmon resonance) cover a large bandwidth in the whole visible wavelength region due to the existence of "hot spots" located at the end of the tips. In this context, gold nanostars appear to be interesting objects. However, their study remains difficult, mainly due to complicated synthetic methods and further functionalization. This paper reports the synthesis, functionalization, and photophysics of luminescent hybrid gold nanostars prepared using a layer-by-layer (LbL) deposition method for the tuning of chromophore-to-particle distances together with the impact of the spectral overlap between the plasmon and the emission/absorption of the dyes. Several luminescent dyes with different optical signatures were selectively adsorbed at the nanoparticle surface. The optimized systems, exhibiting the highest luminescence recovery, clearly showed that overlap must be as low as possible. Also, the fluorescence intensities were quenched in close vicinity of the metal surface and revealed a distance-dependence with almost full recovery of the dyes emission for 11 LbL layers, which corresponded to 15 nm distances evaluated on dried samples. The photophysics of the luminescent core-shell particles were carried out in suspension and correlated with the response of isolated single objects.
- Published
- 2013
- Full Text
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43. Synthesis of PEGylated gold nanostars and bipyramids for intracellular uptake.
- Author
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Navarro JR, Manchon D, Lerouge F, Blanchard NP, Marotte S, Leverrier Y, Marvel J, Chaput F, Micouin G, Gabudean AM, Mosset A, Cottancin E, Baldeck PL, Kamada K, and Parola S
- Subjects
- Animals, Cell Line, Tumor, Cetrimonium, Cetrimonium Compounds chemistry, Endocytosis, Gold pharmacokinetics, Histocytochemistry, Materials Testing, Mice, Nanostructures ultrastructure, Particle Size, Polyethylene Glycols chemistry, Quaternary Ammonium Compounds chemistry, Spectrophotometry, Ultraviolet, Surface-Active Agents chemistry, Gold chemistry, Metal Nanoparticles chemistry, Nanostructures chemistry
- Abstract
A great number of works have focused their research on the synthesis, design and optical properties of gold nanoparticles for potential biological applications (bioimaging, biosensing). For this kind of application, sharp gold nanostructures appear to exhibit the more interesting features since their surface plasmon bands are very sensitive to the surrounding medium. In this paper, a complete study of PEGylated gold nanostars and PEGylated bipyramidal-like nanostructures is presented. The nanoparticles are prepared in high yield and their surfaces are covered with a biocompatible polymer. The photophysical properties of gold bipyramids and nanostars, in suspension, are correlated with the optical response of single and isolated objects. The resulting spectra of isolated gold nanoparticles are subsequently correlated to their geometrical structure by transmission electron microscopy. Finally, the PEGylated gold nanoparticles were incubated with melanoma B16-F10 cells. Dark-field microscopy showed that the biocompatible gold nanoparticles were easily internalized and most of them localized within the cells.
- Published
- 2012
- Full Text
- View/download PDF
44. Aqueous suspensions of GdPO4 nanorods: a paramagnetic mineral liquid crystal.
- Author
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Abécassis B, Lerouge F, Bouquet F, Kachbi S, Monteil M, and Davidson P
- Abstract
Colloidal suspensions of rod-like nanoparticles are well-known to readily form liquid-crystalline phases. Using mineral nanoparticles for this purpose may impart their liquid-crystalline suspensions with original physical properties. We synthesized GdPO(4) nanorods whose aqueous suspensions spontaneously organize in a nematic phase at high concentrations. The nematic phase is very well aligned by small magnetic fields, and the isotropic phase displays a very large field-induced birefringence. Moreover, the nanorods migrate to regions of high magnetic field. On the basis of magnetization measurements, we show that this unusual behavior is due to the fact that GdPO(4) nanorods are actually paramagnetic. Such a paramagnetic mineral liquid crystal, easily synthesized and little sensitive to temperature, may be an interesting alternative to organometallic thermotropic liquid crystals for applications where magnetic field alignment would be more suitable than electric field alignment.
- Published
- 2012
- Full Text
- View/download PDF
45. Silica hybrid sol-gel materials with unusually high concentration of Pt-organic molecular guests: studies of luminescence and nonlinear absorption of light.
- Author
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Chateau D, Chaput F, Lopes C, Lindgren M, Brännlund C, Öhgren J, Djourelov N, Nedelec P, Desroches C, Eliasson B, Kindahl T, Lerouge F, Andraud C, and Parola S
- Abstract
The development of new photonic materials is a key step toward improvement of existing optical devices and for the preparation of a new generation of systems. Therefore synthesis of photonic hybrid materials with a thorough understanding and control of the microstructure-to-properties relationships is crucial. In this perspective, a new preparation method based on fast gelation reactions using simple dispersion of dyes without strong covalent bonding between dye and matrix has been developed. This new sol-gel method is demonstrated through synthesis of monolithic siloxane-based hybrid materials highly doped by various platinum(II) acetylide derivatives. Concentrations of the chromophores as high as 400 mM were obtained and resulted in unprecedented optical power limiting (OPL) performance at 532 nm of the surface-polished solids. Static and time-resolved photoluminescence of the prepared hybrid materials were consistent with both OPL data and previous studies of similar Pt(II) compounds in solution. The impacts of the microstructure and the chemical composition of the matrix on the spectroscopic properties, are discussed.
- Published
- 2012
- Full Text
- View/download PDF
46. Synthesis, electron tomography and single-particle optical response of twisted gold nano-bipyramids.
- Author
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Navarro JR, Manchon D, Lerouge F, Cottancin E, Lermé J, Bonnet C, Chaput F, Mosset A, Pellarin M, and Parola S
- Subjects
- Nanotechnology methods, Particle Size, Electron Microscope Tomography, Gold chemistry, Nanostructures chemistry, Surface Plasmon Resonance methods
- Abstract
A great number of works focus their interest on the study of gold nanoparticle plasmonic properties. Among those, sharp nanostructures appear to exhibit the more interesting features for further developments. In this paper, a complete study on bipyramidal-like gold nanostructures is presented. The nano-objects are prepared in high yield using an original method. This chemical process enables a precise control of the shape and the size of the particles. The specific photophysical properties of gold bipyramids in suspension are ripened by recording the plasmonic response of single and isolated objects. Resulting extinction spectra are precisely correlated to their geometrical structure by mean of electron tomography at the single-particle level. The interplay between the geometrical structure and the optical properties of twisted gold bipyramids is further discussed on the basis of numerical calculations. The influence of several parameters is explored such as the structural aspect ratio or the tip truncation. In the case of an incident excitation polarized along the particle long axis, this study shows how the plasmon resonance position can be sensitive to these parameters and how it can then be efficiently tuned on a large wavelength range.
- Published
- 2012
- Full Text
- View/download PDF
47. Synthesis and fluorescence emission of neutral and anionic di- and tetra-carboranyl compounds.
- Author
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Lerouge F, Ferrer-Ugalde A, Viñas C, Teixidor F, Sillanpää R, Abreu A, Xochitiotzi E, Farfán N, Santillan R, and Núñez R
- Subjects
- Boron Compounds chemistry, Crystallography, X-Ray, Luminescent Agents chemistry, Magnetic Resonance Spectroscopy, Models, Molecular, Spectrometry, Fluorescence, Boron Compounds chemical synthesis, Luminescent Agents chemical synthesis
- Abstract
A new family of photoluminescent neutral and anionic di-carboranyl and tetra-carboranyl derivatives have been synthesized and characterized. The reaction of α,α'-bis(3,5-bis(bromomethyl)phenoxy-m-xylene with 4 equiv. of the monolithium salt of 1-Ph-1,2-C(2)B(10)H(11) or 1-Me-1,2-C(2)B(10)H(11) gives the neutral tetracarboranyl-functionalized aryl ether derivatives closo-1 and closo-2, respectively. The addition of the monolithium salt of 1-Ph-1,2-closo-C(2)B(10)H(11) to α,α,'-dibromo-m-xylene or 2,6-dibromomethyl-pyridine gives the corresponding di-carboranyl derivatives closo-3 and closo-4. These compounds, which contain four or two closo clusters, were degraded using the classical method, KOH in EtOH, affording the corresponding nido species, which were isolated as potassium or tetramethylammonium salts. All the compounds were characterized by IR, (1)H, (11)B and (13)C NMR spectroscopy, and the crystal structure of closo-3 was analysed by X-ray diffraction. The carboranyl fragments are bonded through CH(2) units to different organic moieties, and their influence on the photoluminescent properties of the final molecules has been studied. All the closo- and nido-carborane derivatives exhibit a blue emission under ultraviolet excitation at room temperature in different solvents. The fluorescence properties of these closo and nido-derivatives depend on the substituent (Ph or Me) bonded to the C(cluster), the solvent polarity, and the organic unit bearing the carborane clusters (benzene or pyridine). In the case of nido-derivatives, an important effect of the cation is also observed.
- Published
- 2011
- Full Text
- View/download PDF
48. Photodynamic therapy and two-photon bio-imaging applications of hydrophobic chromophores through amphiphilic polymer delivery.
- Author
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Gallavardin T, Maurin M, Marotte S, Simon T, Gabudean AM, Bretonnière Y, Lindgren M, Lerouge F, Baldeck PL, Stéphan O, Leverrier Y, Marvel J, Parola S, Maury O, and Andraud C
- Subjects
- Alkynes pharmacology, Alkynes therapeutic use, Aniline Compounds pharmacology, Aniline Compounds therapeutic use, Animals, Anthracenes pharmacology, Anthracenes therapeutic use, Apoptosis, Bromobenzenes pharmacology, Bromobenzenes therapeutic use, Cell Line, Tumor, Fluorescent Dyes chemistry, Hydrophobic and Hydrophilic Interactions, Microscopy, Fluorescence, Nanoparticles chemistry, Neoplasms drug therapy, Photochemotherapy, Photons, Photosensitizing Agents pharmacology, Photosensitizing Agents therapeutic use, Poloxamer chemistry, Quantum Theory, Rats, Singlet Oxygen metabolism, Alkynes chemistry, Aniline Compounds chemistry, Anthracenes chemistry, Bromobenzenes chemistry, Photosensitizing Agents chemistry, Polymers chemistry
- Abstract
The synthesis and photophysical properties of two lipophilic quadrupolar chromophores featuring anthracenyl (1) or dibromobenzene (2) were described. These two chromophores combined significant two-photon absorption cross-sections with high fluorescence quantum yield for 1 and improved singlet oxygen generation efficiency for 2, in organic solvents. The use of Pluronic nanoparticles allowed a simple and straightforward introduction of these lipophilic chromophores into biological cell media. Their internal distribution in various cell lines was studied using fluorescence microscopy and flow-cytometry following a successful staining that was achieved upon 2 h of incubation. Finally, multiphoton excitation microscopy and photodynamic therapy capability of the chromophores were demonstrated by cell exposure to a 820 nm fs laser and cell death upon one photon resonant irradiation at 436 ± 10 nm, respectively.
- Published
- 2011
- Full Text
- View/download PDF
49. Transparent plasmonic nanocontainers protect organic fluorophores against photobleaching.
- Author
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Zaiba S, Lerouge F, Gabudean AM, Focsan M, Lermé J, Gallavardin T, Maury O, Andraud C, Parola S, and Baldeck PL
- Subjects
- Animals, Cattle, Fluorescence, Fluorescent Dyes chemistry, Gold chemistry, Light, Metal Nanoparticles chemistry, Nanostructures chemistry, Photobleaching, Rhodamines chemistry, Serum Albumin, Bovine chemistry, Surface Plasmon Resonance, Time Factors, Ultraviolet Rays, Nanotechnology methods, Organic Chemicals chemistry
- Abstract
Numerous research efforts are investigating the possibility of using light interactions with metallic nanoparticles to improve the fluorescence properties of nearby molecules. Few investigations have considered the encapsulation of molecules in metallic nanocavities. In this paper, we present the optical properties of new hybrid nanoparticles consisting of gold nanoshells and fluorescent organic dyes in their liquid cores. Microspectroscopy on single nanoparticle demonstrates that the extinction spectra are in good agreement with Mie's theory. Finite difference time domain (FDTD) calculations reveal that excitation and emission radiations are efficiently transmitted through the thin gold nanoshells. Thus, they can be considered as transparent plasmonic nanocontainers for photoactive cores. In agreement with FDTD calculations, measurements show that fluorophores encapsulated in gold nanoshells keep their brightness, but they show fluorescence lifetimes 1 order of magnitude shorter. As a salient consequence, the photoresistance of encapsulated organic dyes is also improved by an order of magnitude. This unusual ultraviolet photoresistance results from the reduced probability of triplet-singlet conversion that eventually exposes dyes to singlet oxygen photodegradation.
- Published
- 2011
- Full Text
- View/download PDF
50. Rare earth fluoride nanoparticles obtained using charge transfer complexes: a versatile and efficient route toward colloidal suspensions and monolithic transparent xerogels.
- Author
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Chaput F, Lerouge F, Tusseau-Nenez S, Coulon PE, Dujardin C, Denis-Quanquin S, Mpambani F, and Parola S
- Abstract
Crystalline rare earth fluoride nanoparticles were synthesized by reacting rare earth ions with charge-transfer complexes, in solution, under mild conditions. An infrared study showed that these intermediate complexes are made up of solvent molecules (amide: N,N-dimethylformamide, 1-methyl-2-pyrrolidinone, etc.) and fluoride ions coming from hydrofluoric acid. The size and shape of the particles can be controlled through the process parameters. The complete study of the particles obtained through this process is carried out in this document, especially for the YbF(3) system. However, the process can easily be extended to the whole series of rare earth elements. We also show the ability of these objects to be transferred from an aqueous medium to an organic phase thanks to their surface modification. Finally, transparent monolithic xerogels of rare earth fluoride have been developed starting from the prepared colloidal solutions.
- Published
- 2011
- Full Text
- View/download PDF
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