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Hélène Yockell-Lelièvre

Hélène Yockell-Lelièvre
Stratuscent Inc, Montreal, Canada

PhD

About

34
Publications
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627
Citations

Publications

Publications (34)
Article
Tungsten oxide (WO3) nanofibers with cylindrical (400±200nm diameter) and ribbon-like (80±10nm thick ribbons with the width-to-thickness ratio of up to 50:1) shapes were prepared by annealing electrospun polyvinylpyrrolidone/ammonium metatungstate (PVP/AMT) fibers with 1:1 PVP/AMT weight ratio. The effects of annealing temperature (573-1173K), time...
Article
The Raman intensity fluctuations are the initial source of a lack of accuracy or reproducibility of SERS based nanosensors to reliably estimate the molecular concentration in microfluidics. Here, we show that the statistical analysis of the weighting of Raman scattering of the probed molecules compared to the photoluminescence of gold nanoparticles...
Article
Tungsten oxide (WO3) nanofibers with shapes ranging from cylindrical to ribbon-like were prepared by annealing electrospun polyvinylpyrrolidone/ammonium metatungstate (PVP/AMT) fibers. Formation of periodically folded “zigzag” patterns in PVP/AMT and WO3 ribbon-like fibers was observed for the first time at the initial stage of the electrospinning...
Article
Full-text available
Sensing of methotrexate at clinically-relevant concentrations was achieved with a plasmon-coupling assay. In this assay, free methotrexate and folic acid Au nanoparticles competed for human dihydrofolate reductase (hDHFR)-functionalized Au nanoparticles (Au NP). The hDHFR-functionalized Au NPs were immobilized on a small glass sensor inserted in a...
Article
Full-text available
The ability to detect small molecules in a rapid and sensitive manner is of great importance in the field of clinical chemistry, and the advancement of novel biosensors is key to realising point-of-care analysis for essential targets. Testosterone is an example of such a small molecule, the detection of which is important in both clinical analysis,...
Article
Gold nanoparticles (NPs) coated with thiol-terminated polystyrene chains of varying molar mass were added to polystyrene-b-polymethylmethacrylate (PS-b-PMMA) block copolymer monolayers at the air–water interface. Composite films were transferred to solid substrates by the Langmuir–Blodgett technique. For most of the investigated systems, TEM microg...
Article
Plasmonic substrates on a solid support are ideally suited for several biosensing applications. The properties of nanohole arrays and nanoparticle arrays will be demonstrated for SPR sensing and surface enhanced spectroscopies (fluorescence and Raman).
Article
The rapid, label-free and point-of-care detection of therapeutic drugs and other metabolites is of high importance for improving treatment of patients. SPR sensors were developed on a portable instrument for methotrexate, testosterone and antibiotic.
Article
A term project was introduced in teaching advanced spectroscopy and notions of nanotechnology to chemistry students at the graduate level (M.Sc. and Ph.D.). This project could also be suited for an honor's thesis at the undergraduate level. Students were assigned a unique combination of nanoparticle synthesis (13 nm Au nanospheres, similar to 100 n...
Article
Integrating a SERS immunoassay on a plasmonic "patch clamp" nanopipette enabled nanobiosensing for the detection of IgG. A SERS response was obtained using a sandwich assay benefiting from plasmon coupling between a capture Au nanoparticle (AuNP) on a nanotip and a second AuNP modified with a Raman active reporter and an antibody selective for IgG....
Article
In this contribution, we report the identification of the principal reference Raman spectra of a single cystein molecule. To that purpose, we design an active Surface Enhanced Raman Spectroscopy (SERS) template based on surfactant-less Chebyshev nanoparticles operating in a microfluidic platform. A principal component analysis is obtained from fluc...
Article
Full-text available
We report here an original single-step process for synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared with Polystyrene (PS) - Polymethylmethacrylate (PMMA) copolymer, thiolated PS and Propylene Glycol Methyl Ether Acetate (PGMEA) as solvent. The spin-coating and annealing of this solution al...
Article
Full-text available
We report here an original single-step process for synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared with Polystyrene (PS) - Polymethylmethacrylate (PMMA) copolymer, thiolated PS and Propylene Glycol Methyl Ether Acetate (PGMEA) as solvent. The spin-coating and annealing of this solution al...
Article
Full-text available
Near-field plasmon coupling between neighboring gold nanoparticles, measured by polarized optical waveguide lightmode spectroscopy, is employed to study the surface self-assembly of alcanethiol-capped gold nanoparticles during solvent evaporation. The waveguide used is a monomode optical fiber half-coupler. The sample is deposited on the surface of...
Article
Full-text available
The investigation of the Localized Surface Plasmon Resonance for plasmonic nanoparticles has opened new perspectives for optical nanosensors. Today, an issue in plasmonics is the development of large scale and low cost devices. We focus here on the Langmuir-Blodgett technique to self-organize gold nanoparticles (~ 7 nm) into rings (~ 60 nm) via pol...
Article
The plasmonic properties of single Au triangular nanoprisms are investigated using photoemission electron microscopy with particular emphasis on polarization dependence. Two localized surface plasmon resonances (LSPRs) are studied, namely, the in-plane dipolar and quadrupolar plasmon excitations. Experimental maps of the near-field spatial distribu...
Article
Metal nanoparticles are self-assembled into plasmonic nanorings using an evaporation-driven bottom-up approach. Arrays of rings with controllable diameter and pitch are obtained over large areas. Their optical resonances are then characterized.
Article
Full-text available
In this study, amorphous carbonaceous nanoparticles were prepared by a simple hydrothermal process using glucose as precursor. The nearly perfect spherical particles (beads) with the dimensions in the range of 10-500 nm were obtained depending on the main process parameters (precursor concentration, temperature, and time). The particles size, surfa...
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Full-text available
Metallic nanoparticles are self-assembled into plasmonic nanorings. The self-assembly is evaporation-induced and is driven using a template of dielectric microspheres. We obtain well-ordered arrays of metallic nanorings over large areas. The inner and outer diameters of the rings, as well as the pitch of the array, are fully controllable. The optic...
Article
Carbon nanostructures, e.g., nanotubes, fullerenes, carbon blacks, etc., are being extensively explored for numerous biomedical applications. The most of such studies, however, deal with carbon nanotubes, and comparatively less is known on the biomedical potential of other nanosize carbon particles. In the present work, carbon and metal/carbon core...
Article
Glass-deposited monolayers of polystyrene-coated gold nanoparticles with controlled interparticle distance have been prepared. Normal incidence extinction spectra show a progressive red shift of the plasmon resonance wavelength as the interparticle gap within the film is reduced. Polarized extinction spectra were measured at in-plane incidence usin...
Article
Thiol end-functionalized polystyrene chains have been introduced onto the surface of gold nanoparticles via a two-step grafting-to method. This simple grafting procedure is demonstrated to be efficient for gold nanoparticles of different sizes and for particles initially dispersed in either aqueous or organic media. The method has been applied succ...
Article
Full-text available
Gold nanoparticles with shapes which varied from spheres to multipods and polygons were prepared with a seedless approach in water/methanol mixtures in the presence of polyvinyl alcohol using sodium ascorbate as the reducing agent. The shape of Au nanoparticles is critically affected by the water/methanol ratio, as well as by the ratio of hydrogen...
Article
Surface films of organically coated silver nanoparticles, when supported by a liquid substrate, exhibit properties of interest for the fabrication of a new class of liquid mirrors. The development of such mirrors clearly requires the optimization of film reflectivity and stability. The present article reports the dependence of film reflectivity on...
Article
Full-text available
The hydroxyapatite (HA) based bioceramic materials are usually prepared at high sintering temperatures to attain suitable mechanical properties. The sintering process usually results in a material which is compositionally and morphologically different from nonstoichiometric nano-crystalline HA phase of hard tissue. At the same time, HA particulates...
Article
Full-text available
We describe a new technology for the fabrication of inexpensive high-quality mirrors. We begin by chemically producing a large number of metallic nanoparticles coated with organic ligands. The partides are then spread on a liquid substrate where they self-assemble to give optical quality reflective surfaces. Since liquid surface can be modified by...
Article
Full-text available
We describe a technology for the fabrication of inexpensive and versatile mirrors through the use of a new type of nanoengineered optical material composed by the spreading of a self-assembling reflective colloidal film spread at the surface of a liquid. These new reflecting liquids offer interesting possibilities for astronomical instrumentation....
Article
In this paper we present preliminary results on a new type of optical material. By combining a thin reflective colloidal film with a superparamagnetic liquid known as a ferrofluid, it is possible to produce an optical quality surface that can be shaped by the application of a magnetic field. Ferrofluids are colloidal suspensions of nanometer-sized...
Article
Full-text available
The trend towards ever larger telescopes and more advanced adaptive optics systems is driving the need for deformable mirrors with a large number of low cost actuators. Liquid mirrors have long been recognized a potential low cost alternative to conventional solid mirrors. By using a water or oil based ferrofluid we are able to benefit from a stron...

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