The IPGG funds scientific projects where nano- and micro-fluidics play a central role in the research teams. During the 1st phase of the IPGG Labex from 2012 to 2017, 6 calls for projects were launched. They allowed 40 doctoral and postdoctoral grants to be awarded.
The 2nd phase of the Labex IPGG was launched in 2020 thanks to the renewal of the Labex in 2019. Since 2020, 17 projects have been funded.
We will prepare concentrated emulsions of different structures with a microfluidic device, which can further be cross-linked, in order to make model amorphous 2D materials with controlled density and cohesiveness. These amorphous structures will have a « basic atom » of size ~50µm. They will be fractured in a controlled way, and plastic events, i.e. local irreversible rearrangements occurring around the crack tip, will be observed in conventional and confocal microscopy. Their influence on the fracture path and on the fracture dynamics will be studied. The obtained results will be compa-red to theoretical predictions, and to the results of numerical simulations. This study could be the basis of constitutive laws for soft amorphous materials.
Fungi are ubiquitous in our environment. The fascinating ability of these organisms to produce extended filamentous networks is at the origin of their massive colonization of the biosphere and one of the keys to their pathogenicity. We propose in this collaborative project a biophysical study of filamentous growth of the human microbiota fungus Candida albicans. A first objective will be to use microfluidic tools to develop a set of quantitative biophysical observables of the growth of C. albicans. In a second step, we will carry out an "organ-on-chip" approach to study the interactions between hyphae and animal (epithelial, dendritic) cells. Our goal is to develop new experimental and conceptual tools allowing a fine phenotypic characterization of filamentous fungi associated with their genotype, as well as a deeper understanding of the mechanisms associated with their invasive properties.
The depletion of fossil fuel resources and its increase in global demand lead to the development of alternative sustainable energies replacing fossil fuel. The biofuels, such as the ethanol and butanol, have recently attracted great attention, both in fundamental researches and industrial applications. Biofuels are attractive due their diverse resources, such as sugarcane, wheat, corn, lignocellulosic biomass, and crop waste residues. Standard technologies to produce and purify biofuels (fermentation and pervaporation), however, are not very efficient energetically. While membrane reverse osmosis approaches would be much less costly, the attempts to fabricate membranes that are semi-permeable to ethanol but not to water were merely unsuccessful. In this project, we propose here to develop a new class of membranes made of a multistack of graphene and graphene-oxide layers for the separation of water-ethanol mixtures. Based on a theoretical and numerical prediction obtained in our team, showing that GO membrane are self-semi-permebale, we expect this graphitic membrane to allow for the separation of water from alcohol across this membrane. Preliminary experimental result confirm this unique property, which remain to be thoroughly investigated. This is the aiom of the present project. It will allow to develop a completely new and highly attractive method for water-ethanol separation.
Actually, the daily exposure of ultrafine particles to human body goes from 20 to 500 g/m3 and the respiratory system is certainly the most critical route of such an exposure. While the fine particle passages through the alveolar epithelium barrier is the key issue for non-desired inhalation, the pharmacological delivery of drug through lung system is one of important subjects in nanomedicine. In both cases, there is still a lack of mechanistic understanding about the interactions of nanoparticles with human pulmonary alveolar barrier. To overcome this shortage, we propose an in-vitro model made of human alveolar epithelium and endothelium formed on a monolayer of elastic fibers which mimic structurally and functionally the human alveolus. In particular, we propose to use human induced pluripotent stem cells (hiPSC) and microfluidic device to build alveoli-on-chip systems, together with a high precision flow control setup, to study nanoparticles crossing alveolar barrier.
The objective of the work is to synthesize organic compounds using CO2 as a raw material in gas-liquid plasma milli-reactors, a totally new technology developped these last years in IPGG. There is now a great interest to produce CO from CO2 and directly uses in-situ CO molecules as a reactant for synthesis reactions of industrial interest. In that context, the project aims to study the plasma dissociation of CO2 into CO followed by the direct reaction of CO with organic molecules injected as liquids in the diphasic plasma micro-reactors. Two chemical routes will be explored: (i) a well known catalyzed liquid phase reaction currently used for the synthesis of biologically relevant compounds (a classical aminocarbonylation reaction catalyzed by Palladium) and (ii) gas phase reactions between CO and the plasma-generated radicals formed from selected organic substrates.
Miniaturized devices have enormous benefits since they save time and reduce the consumption of reagents and solvents, but they also lead to a dramatic decrease in the separation power and in the injected amounts, which is a serious limitation when the target analytes are at trace-levels in complex samples. This project aims to integrate a sample pretreatment step to extract and concentrate the target analytes, based on a selective mechanism with molecularly and ion imprinted polymers synthesized in situ, to prevent from the simultaneous extraction and concentration of interfering compounds. After optimizing the synthesis conditions, the protocols to selectively extract and preconcentrate the target analytes present in complex real samples will be optimized and validated. Next, the target analytes will be released and will be separated and specifically detected with a printed electrode or by LED induced fluorescence after complexation with a custom-developed probe. Both high selectivity of the polymers and specificity of the detection modes should compensate for the lack of performance of the microsystem separation step. Dopamine and other neurotransmitters in biological samples and lanthanide ions in environmental samples will be the model analytes and samples of this project.
Fitness landscapes determine evolutionary dynamics, in analogy to energy potential landscapes that rule dynamics of physical systems. Given their extremely high dimension (typically 10200), mapping exhaustively protein fitness landscapes and harnessing their local and global structure is impossible. Thus, how much local fitness gradients can be used to infer long term Evolution is still an open question. Here we will probe the local fitness landscape gradient near 103 protein-encoding genes by characterizing phenotypic properties of their sequence space neighborhoods. For this, we will measure the individual phenotype of thousands of point mutants in their neighborhood following our droplet microfluidics-based large-scale genotype-phenotype mapping strategy. Next we will relate the outcome of many long-term evolution trajectories starting from each original gene with the local fitness gradients in their neighborhood. We will next set up an extension of our technology to directly select genes according to the phenotypic distribution and local fitness gradient in their neighborhood (instead of their current fitness), opening up to the direct selection for evolvability of protein-encoding genes.
Two-phase flows are involved in many industrial processes (cosmetics, food, new materials, enhanced oil recovery) and are largely studied since several decades. These studies strongly benefit from the emergence of microfluidics, offering building block experiments or model systems for both single bubble/droplet system or foam/emulsions. These studies lead to both important fundamental questions and to a wide spectrum of applications. The question we address is the influence of the used surfactant (soluble or not) on the global dynamics of these objects. There is no consensus in the literature and we propose to study model systems starting from a building block experiment: a single droplet. The results should have a significant impact for both the droplet –based microfluidics, and more generally to the soft matter community.
Our project aims to reproduce the mechanical constraints induced by growing cysts on quiescent epithelial cells, leading to their entrance in a proliferative cycle and to the generation of new cysts. This ‘snowball” effect leads to renal failure in the most common hereditary nephropathy, ADPKD (Autosomal Dominant Polycystic Kidney Disease). We will study innovative aspects of this cystic spiral by developing a biomimetic system of deformable parallel multi-tubes, mimicking the physiological organization of tubules and their compression by expanding cysts, thanks to original microfabrication and microfluidic approaches. We will characterize the events involved in tubular deformations and generation of new cysts by quantitative imaging and single cell transcriptomics.
The vivid need in fresh water is one of the main challenges now faced by humanity. Water desalination and water recycling involve costly separation processes in terms of energy. The domain has been boosted over the last two decades by the progresses made in membrane technologies for water purification, such as reverse osmosis or nano- and ultra- filtration [1], and more recently by the possibilities offered by nanoscale materials, such as graphene or advanced membranes [2, 3]. However, a necessary step for progress requires out-of-the-box ideas beyond sieving separation principles.
In this projet our aim is to fabricate a biomimetic device mimicking one of the most efficient filtration devices: the kidney [4]. We showed recently in a theoretical investigation, see Ref. [5], that the central piece of the kidney filtration, the U-shaped loop of Henle, is designed as an active osmotic exchanger: accordingly, the waste is separated from water and salt via a symbiotic reabsorbtion, with salt playing the role of an ”osmotic activator” [5]. Beyond, we showed that this design allows to operate at a remarkably small energy cost, typically one order of magnitude smaller than traditional sieving processes like nanofiltration, while working at much smaller pressures.
Taking a biomimetic perspective, we now want to take inspiration from this design and fabricate experimentally a microfluidic artificial counterpart of the kidney filtration process. The design will rely on existing microfabrication technologies and membranes, and use only electric fields as driving forces. This will allow to explore systematically the performance of such a osmotic exchanger in terms of separation of species. Various extensions will be considered. Such a ”kidney on a chip” could be used for compact and low-energy artificial dialytic systems. It also points to new avenues for efficient separation processes and advanced water recycling.
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