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Boudreau, Denis

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Boudreau

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Denis

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Université Laval. Département de chimie

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ncf10368871

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Résultats de recherche

Voici les éléments 1 - 10 sur 16
  • PublicationAccès libre
    A simple and fast compression-based method to fabricate responsive gold-pNIPAM hybrid materials : from thin films to anisotropic microgels
    (Wiley-VCH, 2023-08-04) Sepúlveda, Adolfo; Feller, Déborah; Karg, Matthias; Boudreau, Denis
    In recent years, hydrogel-based soft materials with hybrid properties have found widespread use in various technological fields, including tissue engineering, soft actuators, and flexible electronics. The proper implementation of these smart multifunctional materials into real-world applications requires the development of simple, cost-effective, and large-scale fabrication methods. Herein, a simple compression- and colloid-based method is presented to fabricate responsive Au-poly(N-isopropylacrylamide) (pNIPAM) hybrid films using photopolymerizable resin containing Au-pNIPAM core–shell microgels as building blocks. Uniform Au-pNIPAM hybrid films of 25 × 25 mm with adjustable thickness in the micron-size range (2.3–1.2 µm) w ere successfully fabricated on glass substrates and flexible commercial acetate sheets. The resulting flexible Au-pNIPAM films exhibit robust optical and mechanical properties, even after repeated edge-to-edge bending cycle tests. Additionally, using patterned light to polymerize the Au-pNIPAM films allows synthesizing of anisotropic Au-pNIPAM microgels with high width-to-height aspect ratios, such as square, circular, and rectangular microgels, adding a new dimension to the proposed fabrication method.
  • PublicationAccès libre
    Neighbors Matter : Leveraging Collective Thermoplasmonic Effects for Smart Soft Actuators
    (American Chemical Society, 2024-02-14) Sepúlveda, Adolfo; Boudreau, Denis
    In this work, we are exploring the collective thermoplasmonic properties of small spherical gold nanoparticles embedded into poly(N-isopropylacrylamide) (pNIPAM) films, with a focus on their application as efficient light-driven nano-heaters for smart soft actuation systems. Uniform Au-pNIPAM hybrid films with adjustable thickness in the micrometer range (1 – 22 µm) and distinct concentrations of gold nanoparticles were fabricated by using a photopolymerizable pNIPAM-based resin containing Au-pNIPAM core-shell microgels as building blocks (15-nm diameter gold cores). Upon 520-nm light excitation, the Au-pNIPAM films exhibit a significant temperature increase of up to 75 °C above room temperature at a light irradiance of 116 mW/mm2, as determined by thermal imaging. These results compare well with those obtained with an analytical model describing the rise in temperature produced by neighboring particles in a 3D matrix under continuous illumination, with a relative margin of error of less than 7% for nearly all cases studied. Finally, light-guided swimming robots were fabricated by leveraging the collective photothermal properties of gold nanoparticles in the Au-pNIPAM films. Under light exposure, the trajectory and rotation of swimming robots floating at the air/water interface can be precisely controlled due to the light-induced Marangoni effect, with average speeds of up to 2.5 mm/s for triangular-shaped robots.
  • PublicationAccès libre
    A metal-enhanced Hg2+-responsive fluorescent nanoprobe: from morphological design to application to natural waters
    (American Chemical Society, 2022-06-22) Picard-Lafond, Audrey; Boudreau, Denis; Larivière, Dominic
    Metal-enhanced fluorescence (MEF) is a powerful tool in the design of sensitive chemical sensors by improving brightness and photostability to target-responsive fluorophores. Compounding these advantages with the modest hardware requirements of fluorescent sensing compared to that of centralized elemental analysis instruments, expanding the use of MEF to the detection of low-level inorganic pollutants is a compelling aspiration. Among the latter, monitoring mercury in the environment, where some of its species disseminate through the food chain and, in time, to humans, has elicited a broad research effort towards the development of Hg2+-responsive fluorescent sensors. Herein, a Hg2+-sensitive MEF-enabled probe was conceived by grafting a Hg2+-responsive fluorescein derivative to concentric Ag@SiO2 NPs, where the metallic core enhances fluorescent emission of molecular probes embedded in a surrounding silica shell. Time-resolved fluorescence measurements showed that the fluorophore’s excited state lifetime decreases from 3.9 ns in a solid, coreless silica sphere, to 0.4 ns in the core-shell nanoprobe, granting the dye a better resistance to photobleaching. The Ag-core system showed a sizable improvement in limit of detection at 2 nM (0.4 ppb) compared to 50 nM (10 ppb) in the silica-only colloids and its effectiveness for natural water analysis was demonstrated. Overall, the reported nanoarchitecture hints at the potential of MEF for heavy metal detection by fluorescence detection.
  • PublicationAccès libre
    Revealing the hydrolysis mechanism of a Hg2+-reactive fluorescein probe : novel insights on thionocarbonated dyes
    (American Chemical Society, 2019-12-31) Picard-Lafond, Audrey; Boudreau, Denis; Larivière, Dominic
    As one of the most toxic metal pollutants, mercury is the subject of extensive research to improve current detection strategies, notably to develop sensitive, selective, fast, and affordable Hg2+-responsive fluorescent probes. Comprehending the sensing mechanism of these molecules is a crucial step in their design and optimization of their performance. Herein, a new fluorescein-based thionocarbonate-appended Hg2+-sensitive probe was synthesized to study the hydrolysis reactions involved in the sensing process. Autohydrolysis was revealed as a significant component of the signal generation mechanism, occurring concurrently with Hg2+-catalyzed hydrolysis. This knowledge was used to investigate the effects of key experimental conditions (pH, temperature, chloride ions) on sensing efficiency. Overall, the chemical and physical properties of this new thionocarbonated dye and the insights into its sensing mechanism will be instrumental in designing reliable and effective portable sensing strategies for mercury and other heavy metals.
  • PublicationAccès libre
    Indium@silica core–shell nanoparticles as plasmonic enhancers of molecular luminescence in the UV region
    (RCS, 2013-08-14) Boudreau, Denis; Magnan, François; Fontaine, Frédéric-Georges; Gagnon, Joanie
    Large fluorescence enhancement of UV-active molecular models Carbostyril 124 and tryptophan by core–shell indium-based plasmonic architectures demonstrates the metal's potential in the design of bioprobes. Precise control over the metal–fluorophore distance is achieved through the controlled deposition of a uniform silica layer over the nanosized indium particles
  • PublicationAccès libre
    Enhancing galvanic replacement in plasmonic hollow nanoparticles : understanding the role of the speciation of metal ion precursors
    (Wiley, 2020-04-22) Boudreau, Denis; Richard-Daniel, Josée
    Hollow nanostructures offer great potential for plasmonic applications due to their strong and highly tunable localized surface plasmon resonance. The relationship between the plasmonic properties and geometry of hollow nanoparticles, such as core-shell size ratio, concentricity of the cavity and porosity of the wall, is well documented. Nanoscale galvanic replacement provides a simple, versatile and powerful route for the preparation of such hollow structures. Here we demonstrate how the efficiency of reductant-assisted galvanic replacement processes can be enhanced by controlling the degree of hydration and hydrolysis of the metal ion precursor using pH and pL as key control parameters (by analogy to pH, the letter p in the expression pL is used to indicate the decimal cologarithm associated with the concentration of the ligand L). Adjusting precursor speciation prior to the sacrificial template’s hollowing process offers a new strategy to tune the morphology and optical properties of plasmonic hollow nanostructures.
  • PublicationAccès libre
    Acting as a molecular tailor : dye structural modifications for improved sensitivity towards lysophosphatidic acids sensing
    (American Chemiscal Society, 2022-12-28) Fontaine, Nicolas; Harter, Lara; Marette, André; Boudreau, Denis
    Lysophosphatidic acids (LPA) are key biomarkers for several physiological processes, the monitoring of which can provide insights into the host’s health. Common lab-based techniques for their detection are cumbersome, expensive and necessitate specialized personnel to operate. LPA-sensitive fluorescent probes have been described, albeit for non-aqueous conditions, which impedes their use in biological matrices. In this paper, we explore in detail the influence of structure on the extent of aggregation-induced fluorescence quenching using specially synthesized styrylpyridinium dyes bearing structural adaptations to bestow them enhanced affinity towards LPA in aqueous media. Spectroscopic investigations supported by time-resolved fluorimetry revealed the contribution of excimer formation to the fluorescence quenching mechanism displayed by the fluorescent probes. Experimental observations of the influence of structure on detection sensitivity were supported by DFT calculations.
  • PublicationAccès libre
    Gold speciation and co-reduction control the morphology of AgAu nanoshells in formaldehyde-assisted galvanic replacement
    (American Chemical Society, 2018-08-23) Boudreau, Denis; McCarthy, Lauren A.; Richard-Daniel, Josée; Yazdi, Sadegh; Chagnot, Matthew; Ringe, Emilie
    Hollow AgAu nanostructures have a myriad of potential applications related to their strong and tunable localized surface plasmon resonances. Here, we describe how the hydrolysis of the Au precursor, AuCl4–, produces AuCl4–x(OH)x–, where x is both time and pH-dependent, and how this can be used to control the morphology of hollow nanoshells in the co-reduction-assisted galvanic replacement of Ag by Au. Controlling the degree of hydrolysis is the key to obtain smooth shells: too small values of x (low hydrolysis) yield inhomogeneously replaced rough shells whereas too large values of x lead to the dominance of Au nucleation over galvanic replacement. Kinetic studies reveal two time constants for the galvanic replacement varying with temperature and composition; a short (<10 min) half-life component associated with the initial void creation and a long (>100 min) half-life component associated with the continuous reduction and replacement of Ag. By optimizing the reaction’s pH and Au speciation, we obtained smooth alloy shells with fine control of composition, size, and shape over a broad range, thereby tuning the optical properties. This framework for understanding and controlling reaction kinetics and nanoshell morphology is applicable to other metallic systems and precursors, providing new ways to rationally design nanostructure syntheses.
  • PublicationAccès libre
    Pushing the limits of surface-enhanced raman spectroscopy (SERS) with deep learning : identification of multiple species with closely related molecular structures
    (Society for Applied Spectroscopy, 2022-01-26) Boudreau, Denis; Fillion, Daniel; Fontaine, Nicolas; Fortin, Hubert; Lebrun, Alexis; Barbier, Olivier
    Raman spectroscopy is a non-destructive and label-free molecular identification technique capable of producing highly specific spectra with various bands correlated to molecular structure. Moreover, the enhanced detection sensitivity offered by Surface-Enhanced Raman spectroscopy (SERS) allows analyzing mixtures of related chemical species in a relatively short measurement time. Combining SERS with deep learning algorithms allows in some cases to increase detection and classification capabilities even further. The present study evaluates the potential of applying deep learning algorithms to SERS spectroscopy to differentiate and classify different species of bile acids, a large family of molecules with low Raman cross sections and molecular structures that often differ by a single hydroxyl group. Moreover, the study of these molecules is of interest for the medical community since they have distinct pathological roles and are currently viewed as potential markers of gut microbiome imbalances. A Convolutional Neural Network (CNN) model was developed and used to classify SERS spectra from five bile acid species. The model succeeded in identifying the five analytes despite very similar molecular structures and was found to be reliable even at low analyte concentrations.
  • PublicationAccès libre
    A glycan-based plasmonic sensor for prostate cancer diagnosis
    (Royal Society of Chemistry, 2021-10-01) Lamarre, Mathieu; Bansept, Marc-Antoine; Boudreau, Denis; Tremblay, Thomas; Fradet, Vincent; Giguère, Denis; Robitaille, Karine
    Prostate cancer affects thousands of men who undergo clinical screening tests every year. The main biomarker used for the diagnosis of prostate cancer, prostate specific antigen (PSA), presents limitations that justify investigating new biomarkers to improve reliability. Antibodies against the tumor-associated carbohydrate antigen (Tn), or TACA, develop early in carcinogenesis, making them an interesting alternative as a target for prostate cancer diagnostics. In this work, the Tn antigen was synthesized and immobilized on a surface plasmon resonance sensor coated with a polydopamine/polyethylene oxide mixed layer used both as an anchoring surface for Tn capture moieties and to minimize surface fouling. The sensor could be regenerated and reused at least 60 times without any significant loss in sensitivity. Anti-Tn antibodies were detected in the 0-10 nM concentration range with detection limits of 0.1 and 0.3 nM in spiked buffer solutions and diluted human blood serum samples, respectively. Finally, as a proof-of-concept, this carbohydrate-based sensor was used to successfully discriminate blood serum samples from prostate cancer-free and prostate cancer patients.