Synthèse et caractérisation de systèmes colloïdaux à géométrie coeur/coquille d'indium-silice Vers une application en biodétection

Authors: Magnan, François
Advisor: Boudreau, Denis
Abstract: A notable application of nanomaterials is the use of metallic nanoparticles (NPs) as optical bioprobes in Raman or fluorescence spectroscopy detection schemes. Such a use is permitted by the plasmonic properties shown by these NPs upon light irradiation; the spectroscopic properties of these colloids are tuned through careful selection of the core’s composition, size and environment. Gold and silver are the two most commonly used metals for biodetection as they are easily prepared in nanoscopic regimes with defined shapes and sizes, as well as for their intense optical interactions with visible light. These metals are however not applicable at higher energy UV regimes, which would allow, for instance, the enhancement of the intrinsic fluorescence of proteins, a field of interest in biodetection which is hindered by the extremely low fluorescence signal of these biomolecules. We propose for such an application the use of indium-based plasmonic probes, as this metal has been shown to be active in the UV regime. This master’s thesis thus focuses on the preparation of core-shell colloids for an eventual use in biodetection. The indium cores are prepared in a single step which combines both polyol and hot-injection methods characteristics. By shuffling various synthetic parameters, indium cores approximately 9 and 70 nanometers (nm) wide are obtained. The larger cores, which should demonstrate a stronger fluorescence enhancement effect, are then covered with a silica shell through a single Stöber-like step. Again, controlling different synthetic parameters such was water content, silica precursor concentration, and Stöber system dilution allows to modulate the silica’s thickness between 4 and 40 nm. Such a thin silica shell on such a relatively small indium core is, at the best of our knowledge, still unprecedented. The synthesized core-shell colloids are characterized with UV-Vis spectroscopy, transmission electron microscopy and dynamic light scattering.
Document Type: Mémoire de maîtrise
Issue Date: 2013
Open Access Date: 20 April 2018
Grantor: Université Laval
Collection:Thèses et mémoires

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