Denis Boudreau

Laval University | ULAVAL · Department of Chemistry

Metal-enhanced fluorescence (MEF) is a powerful tool in the design of sensitive chemical sensors by improving brightness and photostability of target-responsive fluorophores. Compounding these advantages with the modest hardware requirements of fluorescence sensing compared to that of centralized elemental analysis instruments, thus expanding the u...

Monitoring antibody response to SARS-CoV-2 is critical for assessing the humoral response, especially important considering the emergence of multiple SARS-CoV-2 variants of concern (VOCs). Herein, we developed microfluidics-integrated multiplexed SERS...

SARS-CoV-2 variants of concern (VOCs) have emerged worldwide, with implications on the spread of the pandemic. Characterizing the cross-reactivity of antibodies against these VOCs is necessary to understand the humoral response of non-hospitalized individuals previously infected with SARS-CoV-2, a population that remains understudied. Thirty-two SA...

The synthesis of core-shell (Fe3O4@SiO2) magnetic nanoparticles (MNP) functionalized using a Schiff base ligand (bis(3-methoxysalicylaldehyde)-o-phenylenediimine; MeOSalophen) for uranium extraction is reported. Extractive performances with respect to pH, adsorption kinetics, chemical nature of the equilibration phase, and elemental selectivity wer...

We report on the development of surface plasmon resonance (SPR) sensors and matching ELISAs for the detection of nucleocapsid and spike antibodies specific against the novel coronavirus 2019 (SARS-CoV-2) in human serum, plasma and dried blood spots (DBS). When exposed to SARS-CoV-2 or a vaccine against SARS-CoV-2, the immune system responds by expr...

SARS-CoV-2 variants of concern (VOCs) have emerged worldwide, with implications on the spread of the pandemic. Characterizing the cross-reactivity of antibodies against these VOCs is necessary to understand the humoral response of non-hospitalized individuals previously infected with SARS-CoV-2, a population that remains understudied. Thirty-two SA...

DNA hybridization phenomena occurring on solid supports are not understood as clearly as aqueous phase hybridizations and mathematical models cannot predict some empirically obtained results. Ongoing research has identified important parameters but remains incomplete to accurately account for all interactions. It has previously been shown that the...

We report on the development of surface plasmon resonance (SPR) sensors and matching ELISAs for the detection of nucleocapsid and spike antibodies specific against the novel coronavirus 2019 (SARS-CoV-2) in human serum, plasma and dried blood spots (DBS). When exposed to SARS-CoV-2 or a vaccine against SARS-CoV-2, the immune system responds by expr...

The implementation of gold-hydrogel core-shell nanomaterials in novel light-driven technologies requires the development of well-controlled and scalable synthesis protocols with precisely tunable properties. Herein, new insights are presented concerning the importance of using the concentration of gold cores as a control parameter in the seeded pre...

The alteration of photophysical properties of fluorophores in the vicinity of a metallic nanostructure, a phenomenon termed plasmon- or metal-enhanced fluorescence (MEF), has been investigated extensively and used in a variety of proof-of-concept demonstrations over the years. A particularly active area of development in this regard has been the de...

There is a growing need for brighter luminescent materials to improve the detection and imaging of biomarkers. Relevant contexts include low-abundance biomarkers and technology-limited applications, where an example of the latter is the emerging use of smartphones and other nonoptimal but low-cost and portable devices for point-of-care diagnostics....

We report a surface plasmon resonance (SPR) sensor detecting nucleocapsid antibodies specific against the novel coronavirus 2019 (SARS-CoV-2) in undiluted human serum. When exposed to SARS-CoV-2, the immune system responds by expressing antibodies at levels that can be detected and monitored to identify the patient population immunized against SARD...

We report a surface plasmon resonance (SPR) sensor detecting nucleocapsid antibodies specific against the novel coronavirus 2019 (SARS-CoV-2) in undiluted human serum. When exposed to SARS-CoV-2, the immune system responds by expressing antibodies at levels that can be detected and monitored to identify the patient population immunized against SARD...

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...

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 performa...

We report the integration of surface plasmon resonance (SPR), cyclic voltammetry and electrochemiluminescence (ECL) responses to survey the interfacial adsorption and energy transfer processes involved in ECL on a plasmonic substrate. It was observed that a Tween® 80/tripropylamine nonionic layer formed on the gold electrode of the SPR sensor, whil...

We report the integration of surface plasmon resonance (SPR), cyclic voltammetry and electrochemiluminescence (ECL) responses to survey the interfacial adsorption and energy transfer processes involved in ECL on a plasmonic substrate. It was observed that a Tween® 80/tripropylamine nonionic layer formed on the gold electrode of the SPR sensor, whil...

Hollow noble metal nanoparticles are of growing interest due to their localized surface plasmon resonance (LSPR) tunability. A popular synthetic approach is galvanic replacement which can be coupled with a co-reducer. Here, we describe the control over morphology, and therefore over plasmonic properties including energy, bandwidth, extinction and s...

A simple chemical process for fabricating patterned gold films inside microfluidic channels and devices

Hollow AgAu nanostructures have a myriad of potential applications related to their strong and tunable localized surface plasmon resonances (LSPRs). 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 present work involves the design of a multifunctional system based on gold nanoshells (AuNSs) decorated with lanthanide-based upconversion nanoparticles (UCNPs) intended as an optical heater and temperature probe at the nanoscale. The synthesis of NaGdF4 UCNPs doped with ions Yb³⁺:Er³⁺ was performed via thermal decomposition of lanthanide fluor...

Fluorescent nanosensors for extracellular ion concentration measurements are disclosed herein. More specifically, a fluorescent nanosensor for extracellular ion measurements comprising a photoluminescent nanostructure disposed on a substrate surface is disclosed. The photoluminescent nanostructure comprises a fluorescent metallic core-silica shell...

Gold core-shell nanoparticles were synthesized based on metallic cores, variable silica shell spacers covered with modified fluorescent silica layers. Ultraluminescent properties were obtained based on metal-enhanced fluorescence (MEF). Different silica spacers were synthesized to optimize the MEF enhancement factor (MEFEF). An optimal MEFEF was de...

A multifunctional nanosystem was synthesized to be used as a dual sensor of UV light and temperature. NaGdF4:Yb³⁺:Er³⁺ upconverting nanoparticles (UCNPs) were synthesized and coated with a silica shell to which a europium(III) complex was incorporated. The synthesis of NaGdF4 UCNPs was performed via thermal decomposition of lanthanide ion fluoride...

The field known as plasmonics has seen a tremendous growth in interest from the research community. One of the more popular topics is the surface plasmon waveguide. As an alternative to solid linear nanostructures, a chain of plasmonic nanoparticles can also be used to propagate a traveling wave of surface charges. Experimentally, plasmonic nanopar...

Core–shell nanoparticles are versatile nanostructures that can be used as luminescent biosensing platforms in many nanotechnological developments. Ultraluminescent fluorescent gold core–shell nanoparticles based on Metal-Enhanced Fluorescence (MEF) were synthesized. The nanoparticles obtained were formed by 40.0 nm cores and variable silica spacer...

Supramolecular chemistry is a well-known field that, applied to analytical chemistry gives, as a result, supramolecular analytical chemistry. Based in its interactions, this field is part of a new area of nanomedicine, called supramolecular medicine. In order to improve the detection of biological molecules to be applied in cell tracking, health pr...

In this work, we designed a ratiometric core-shell nanoarchitecture composed of an indium UV plasmonic core, an internal reference (Rhodamine B), a pH-sensitive probe (fluorescein), and a halide ion sensor (6-methoxyquinolinium). Immobilizing the fluorophores in distinct silica layers at precise distances from the core modulates the plasmon couplin...

The internal structure of hollow AgAu nanorods created by partial galvanic replacement was manipulated reversibly and its effect on optical properties was mapped with nanometer resolution. Using the electron beam in a scanning transmission electron microscope to create solvated electrons in an encapsulated solution-filled cavity in the nanorods, Ag...

Metal@silica concentric nanoparticles capable of metal-enhanced fluorescence (MEF) represent a powerful means to improve the brightness and stability of encapsulated organic fluorophores and are finding numerous applications in biology, analytical chemistry, and medical diagnostics. The rational design of MEF-enabled labels and sensors often involv...

A Nanosensor based on β-cyclodextrin (β-CD) macrocycles linked to gold nanoparticles for Rhodamine B (RhB) sensing was developed applying the metal-enhanced fluorescence effect (MEF). Hence, we have developed many ways to control the distance of supramolecular systems to nanoparticle surface with different bioconjugation strategies in order to opti...

A method for creating pH maps in microchannels containing liquid/liquid and liquid/gas phases comprised of water and CO 2 is demonstrated. It is based on a glass slide coated with nanoparticles exhibiting metal-enhanced fluorescence. The time resolution is better than 500 ms, limited by the fluidic control. This work opens the way for new in situ m...

A microfluidic platform with a fluorescent nanoparticle-based sensor is demonstrated for real-time, ratiometric pH imaging of biofilms. Sensing is accomplished by a thin patterned layer of covalently bonded Ag@SiO2+FiTC nanoparticles on an embedded planar glass substrate. The system is designed to be sensitive, responsive and give sufficient spatia...

BackgroundA point-of-care rapid test (POCRT) may help early and targeted use of antiviral drugs for the management of influenza A infection. Objective(i) To determine whether antiviral treatment based on a POCRT for influenza A is cost-effective and, (ii) to determine the thresholds of key test parameters (sensitivity, specificity and cost) at whic...

Low-polydispersity europium-doped (H3O)Y3F10·xH2O single-crystal nanoparticles can be prepared via a simple reverse microemulsion method. The doping level of the particles can be varied by changing the relative concentration of europium to yttrium in the initial precursor mixture. Doping levels of up to 14 ± 2 at% can be attained without loss of th...

Aims: Calcific aortic valve stenosis (CAVS) is the most common heart valve disease. In the present work we sought to determine the reversibility of mineralization in the aortic valve. Methods and results: By using in vitro analyses we found that valve interstitial cells (VICs) have the ability to resorb minerals. We documented that agonist of P2...

Background and objectives: The last two decades have seen major developments in genotyping assays to facilitate the procurement of red blood cell units to alloimmunized patients. To make genotyping faster, simpler and less costly, a nanotechnology approach based on metal/silica fluorescent nanoparticles and a polymer-based hybridization optical tr...

Covalent “click” cycloaddition was used to functionalize silica substrates with pH-sensitive metallic core-fluorescent shell nanoparticle probes, thus producing uniform and highly luminescent analytical devices usable on both commercial fluorimeters and fluorescence microscopes. Quantitative and spatially-resolved extracellular pH measurements were...

In recent years, various methods for the synthesis of fluorescent core-shell nanostructures were developed, optimized, and studied thoroughly in our research group. Metallic cores exhibiting plasmonic properties in the UV and visible regions of the electromagnetic spectrum were used to increase substantially the brightness and stability of organic...

A biosensor based on a cationic polymer and metal@silica core-shell nanoparticles is demonstrated for the rapid identification of the SRY gene from unamplified human genomic DNA. By amplifying the fluorescence signal triggered by the capture of target molecules, this biosensor avoids the added complexity of enzyme-based chemical amplification, make...

We have demonstrated experimentally that firing a laser filament in a subsaturated zone of a cloud chamber of inversed temperature profile could induce water condensation. Initially, through ion chromatography performed on samples collected from a receptacle placed under the laser, the presence of HNO 3 was observed. The existence of this HNO 3 , a...

We have demonstrated experimentally that firing a laser filament in a subsaturated zone of a cloud chamber of inversed temperature profile could induce water condensation. Initially, through ion chromatography performed on samples collected from a receptacle placed under the laser, the presence of HNO 3 was observed. The existence of this HNO 3 , a...

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 i...

This paper describes the design, functioning and use of a portable detection platform for multiplex nucleic acid testing. The system features a bead-supported DNA hybridization assay performed inside a microfluidic cartridge. Polystyrene particles modified with DNA capture probes are confined in the detection area and exposed to a solution of fluor...