M/F PhD: NIR-fueled fluorescent microbeads for velocity and O2 sensing

Job title:

M/F PhD: NIR-fueled fluorescent microbeads for velocity and O2 sensing

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Job description

Offer DescriptionBioreactor operation can be affected by local concentration gradients of dissolved oxygen and H3O+. O2 is often introduced by bubbling air or pure gas into the medium, and its dissolution depends on local fluid flows. Mapping these, as well as monitoring oxygen and pH, is therefore essential. Local fluid velocity is usually determined using particle image velocimetry (PIV), while local [O2] and pH can be measured optically using fluorescent dyes, which are either quenched by O2 or acidochromic, respectively. Unfortunately, these dyes are generally used in the same visible light range. The subject of this PhD is the preparation and calibration of a set of O2-sensitive PIV beads of different sizes and types, inspired by the ‘SensPIV’ concept but driven in the near-infrared range thanks to the incorporation of up-conversion nanoparticles (UCNPs) developed at Softmat. Thulium-doped UCNPs can convert near-infrared light (i.e. 800 nm) into blue light, spectrally matched to the O2 probe ‘[Ru(bathophen)3)]2+’, a dye used by the TBI team. These beads can therefore be excited independently of the pH indicator in solution. Finally, local fluid flows are also measured optically by particle imaging. The final objective, the mapping of concentration and flow velocity fields, is a matter for analytical chemistry and physics. However, the design and fabrication of the microsphere will involve the preparation of up-converting inorganic nanoparticles coated with a ruthenium complex for O2 detection, and typically belong to the fields of soft matter and nanoscience.This collaborative project between Softmat (UMR5623 CNRS UPS) and the Toulouse Biotechnology Institute, Bio & Chemical Engineering (TBI), CNRS-INSA (UMR 5504)-INRAE (UMR 792), has the following objectives:
1- prepare a set of UCNP-coated microspheres and Ru probes from commercially available microspheres and UCNP nanoparticles and ruthenium complexes
2- calibrate these microprobes as O2 sensors
3- participate in PIV measurements with the TBI laboratory
4- validate the simultaneous monitoring of pH and O2 concentration in a microfluidic device at the TBI laboratory.
In the first phase, the PhD candidate will prepare the micro-sensor components (UCNPs and O2 probe). Based on our preliminary results, the best strategy is to coat the UCNPs with a polymer loaded with the O2 probe before final association with the calibrated PIV beads. The geographical proximity of the two laboratories will ensure regular contacts and meetings. The PhD student will spend most of his time at SOFTMAT, but will soon be allowed to join the TBI team.

The Chemistry of Colloids, Polymers and Complex Assemblies laboratory is dedicated to research into the chemistry of soft matter. It focuses on the design of organized systems composed of surfactants, polymers, biomolecules or nanoparticles. Our skills in analytical chemistry, physical chemistry and photochemistry also enable us to accurately assess the structure/properties relationship of these reactive objects. This research is carried out in frequent collaboration with academic and industrial partners, and contributes to meeting the scientific and societal challenges of our time. The laboratory is based in the south of France, in the city of Toulouse. Visit our website:RequirementsResearch Field Chemistry Education Level Master Degree or equivalentResearch Field Physics Education Level Master Degree or equivalentResearch Field Physics Education Level Master Degree or equivalentLanguages FRENCH Level BasicResearch Field Chemistry » Physical chemistry Years of Research Experience NoneResearch Field Physics » Chemical physics Years of Research Experience NoneResearch Field Physics » Biophysics Years of Research Experience NoneAdditional InformationEligibility criteriaCandidates must hold a Master’s degree in chemistry. Skills required include soft matter physicochemistry (organic and inorganic colloids) and analytical chemistry (assay, photophysics (luminescence)), so a broad scientific curiosity is desirable. Given the interdisciplinary nature of the project, communication skills will be crucial.Additional commentsANR Odysseus contract : “Optimization of carbon Dioxide and oxYgen maSS transfer in biorEactors: a mUltiscale Study”, ANR-23-CE51-0002 Website for additional job detailsWork Location(s)Number of offers available 1 Company/Institute Chimie des colloïdes, polymères et assemblages complexes Country France City TOULOUSE GeofieldWhere to apply WebsiteContact CityTOULOUSE WebsiteSTATUS: EXPIRED

Expected salary

Location

Toulouse

Job date

Fri, 17 May 2024 05:01:32 GMT

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