Publications by authors named "Sebastien Teychene"

Microfluidics has emerged as a robust technology for diverse applications, ranging from bio-medical diagnostics to chemical analysis. Among the different characterization techniques that can be used to analyze samples at the microfluidic scale, the coupling of photonic detection techniques and on-chip configurations is particularly advantageous due to its non-invasive nature, which permits sensitive, real-time, high throughput, and rapid analyses, taking advantage of the microfluidic special environments and reduced sample volumes. Putting a special emphasis on integrated detection schemes, this review article explores the most relevant advances in the on-chip implementation of UV-vis, near-infrared, terahertz, and X-ray-based techniques for different characterizations, ranging from punctual spectroscopic or scattering-based measurements to different types of mapping/imaging.

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Article Synopsis
  • A novel microreactor platform enables extremely fast reagent mixing in under 300 microseconds, allowing for detailed studies of the synthesis of ultra-small gold nanoparticles (NPs).
  • By pairing the microreactor with advanced characterization techniques, researchers can investigate reaction pathways and phase transitions more effectively without the limitations of traditional methods.
  • The study reveals the kinetics of gold nanoparticle formation from Au(III) precursors and identifies the presence of prenucleation clusters and a temporary Au(I) phase, proposing different reaction pathways that bypass classical mechanisms in NP formation.
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The equation of state of colloids plays an important role in the modelling and comprehension of industrial processes, defining the working conditions of processes such as drying, filtration, and mixing. The determination of the equation is based on the solvent equilibration, by dialysis, between the colloidal suspension and a reservoir with a known osmotic pressure. In this paper, we propose a novel microfluidic approach to determine the equation of state of a lysozyme solution.

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It is the ambition of many researchers to finally be able to close in on the fundamental, coupled phenomena that occur during the formation and expression of electrocatalytic activity in electroactive biofilms. It is because of this desire to understand that bioelectrochemical systems (BESs) have been miniaturized into microBES by taking advantage of the worldwide development of microfluidics. Microfluidics tools applied to bioelectrochemistry permit even more fundamental studies of interactions and coupled phenomena occurring at the microscale, thanks, in particular, to the concomitant combination of electroanalysis, spectroscopic analytical techniques and real-time microscopy that is now possible.

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Cooling circuits in many industrial sectors are faced with daily issues of scaling. One preventive treatment consists in injecting a polymer additive in the circuit to inhibit precipitation of calcium carbonate. Among the used additives, very few are "green" and the efficiency of new candidates are difficult to test directly in industrial conditions.

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Sample handling and manipulation for cryoprotection currently remain critical factors in X-ray structural determination. While several microchips for macromolecular crystallization have been proposed during the last two decades to partially overcome crystal-manipulation issues, increased background noise originating from the scattering of chip-fabrication materials has so far limited the attainable resolution of diffraction data. Here, the conception and use of low-cost, X-ray-transparent microchips for in situ crystallization and direct data collection, and structure determination at atomic resolution close to 1.

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Article Synopsis
  • The synthesis of metal nanoparticles using apolar solvents and long chain surfactants effectively controls particle size and shape, but understanding the nucleation and growth mechanisms is complex due to the multiple roles of surfactants.
  • This study utilizes in situ techniques like SAXS, XAS, and HE-XRD to explore the formation of ultra-small gold particles, suggesting that they emerge from stable pre-nucleation clusters (PNCs) rather than following classical nucleation pathways.
  • The research highlights the influence of the oleylamine surfactant on the reactivity and size of gold precursors, establishing its critical role throughout the nanoparticle formation process, including solubilization, size determination, and final particle stabilization.
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The relevance of coupling droplet-based Photonic Lab-on-a-Chip (PhLoC) platforms and Small-Angle X-Ray Scattering (SAXS) technique is here highlighted for the performance of high throughput investigations, related to the study of protein macromolecular interactions. With this configuration, minute amounts of sample are required to obtain reliable statistical data. The PhLoC platforms presented in this work are designed to allow and control an effective mixing of precise amounts of proteins, crystallization reagents and buffer in nanoliter volumes, and the subsequent generation of nanodroplets by means of a two-phase flow.

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A low cost fabrication process for photonic lab on a chip systems is here proposed. For the implementation of the masters suitable for cast molding fabrication, an inexpensive dry film photoresist, patternable using standard laboratory equipment, is benchmarked against standardized SU-8 masters obtained using UV lithography and systems manufacture in clean room facilities. Results show adequate system fabrication and a comparable performance of the photonic structures for absorbance/extinction measurements.

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In this work, we propose the combination of small-angle X-ray scattering (SAXS) and high throughput, droplet based microfluidics as a powerful tool to investigate macromolecular interactions, directly related to protein solubility. For this purpose, a robust and low cost microfluidic platform was fabricated for achieving the mixing of proteins, crystallization reagents, and buffer in nanoliter volumes and the subsequent generation of nanodroplets by means of a two phase flow. The protein samples are compartmentalized inside droplets, each one acting as an isolated microreactor.

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Calcium pyrophosphate hydrate (CPP, Ca(2)P(2)O(7) · nH2O) and calcium orthophosphate compounds (including apatite, octacalcium phosphate etc.) are among the most prevalent pathological calcifications in joints. Even though only two dihydrated forms of CPP (CPPD) have been detected in vivo (monoclinic and triclinic CPPD), investigations of other hydrated forms such as tetrahydrated or amorphous CPP are relevant to a further understanding of the physicochemistry of those phases of biological interest.

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