Cholangiopathies are a significant cause of morbidity and mortality and a major indication for liver transplant. They affect cholangiocytes, the cells lining the biliary system, a tree-shaped network of biliary ducts which carry the bile out of the liver. Due to its complex organization and entanglement with other hepatic cells, biliary tissue specific functions are difficult to assess, making the etiology of several cholangiopathies still elusive. Therefore, the production of bioengineered biliary tissue appears critical. However, neither 2D cultures nor 3D biliary spheres already produced can constitute a relevant model to question among the most important physio-pathological processes like the increase in biliary pressure, the alteration of the epithelial permeability, the exposure to shifted bile acid composition, inflammation or toxic drugs such as some antibiotics. Preliminary work within the consortium resulted in the bioprinting of bile tubes lined with rat cholangiocytes. Based on this breakthrough, our project aims to produce a model to study the pathogenesis of the biliary epithelium, by connecting bile tubes bio-printed with rat or human cholangiocytes differentiated from iPSCs, to an external microfluidic system where the flow can be measured and finely regulated. The effects of pathological conditions such as increased fluid pressure, the introduction of toxic bile compounds or antibiotics, or the invalidation of tight junction genes will be evaluated in terms of functionality, permeability, homeostasis. and regeneration of the biliary epithelium. The consortium relies on complementary expertise in biliary bioengineering, microfluidics, clinical hepatology, differentiation of hiPSCs into hepatic cells, biliary homeostasis and pathophysiology in vitro and in mouse models.

In metal additive manufacturing by laser powder bed fusion, the mechanical characteristics and geometry of the produced parts are generated during the manufacturing process. These two aspects are greatly influenced by the laser spot trajectories and by the local control of the energy provided to the powder. The numerical control unit, which generates the instructions to be sent to the actuators, has therefore a significant impact on the quality of the produced parts. An analysis of several industrial numerical control units employed in additive manufacturing has shown that the internal treatments can induce local over-melting leading to a deterioration in the quality of the produced parts. The ORACLE project therefore aims to develop a numerical control unit for laser powder bed fusion process. More specifically, the aim is to model and natively integrate the machine (galvanometers and laser source), process and production constraints into the operations carried out by the numerical control unit. The goal of this work is to locally control the energy provided to the powder during fusion. To achieve this objective, the project intends to remove the following scientific and technological barriers: 1) to develop a control solution to pilot the actuators and 2) to locally optimise the laser trajectories and power, by taking into account the machine and process constraints. Through these two challenges, the ORACLE project aims to highlight the impact of the various operations carried out in the NC in additive manufacturing and to build a control architecture that can address current and future technical and scientific issues.

Superfluorescence (SF) refers to a well-known phenomenon in atomic physics in which emitters can synchronously emit photons through their long-range interaction, resulting in accelerated and bright coherent emission. The SF process should be theoretically efficient by combining similar emitters with large dipole moment within a superlattice, but experimentally strong limitations arise from their organization within an assembly, due to the difficulties of obtaining spectrally identical individual emitters with high densities and identical dipole orientations. The control of the inter-emitter distance is also a key parameter, with a trade-off between the necessary electromagnetic coupling and the detrimental electronic coupling. That is why in solid-state physics, SF has been demonstrated in very limited systems. Recently, perovskite nanocrystal (pNC) superlattices have joined this shortlist, thanks to their optimal optical and structural properties. Nevertheless, a critical frontier remains unexplored: the demonstration of cavity-enhanced SF of pNC superlattices coupled to a photonic structure. To tackle this challenge, CSUPER2 aims to integrate pNC superlattices into an open fibered-microcavity specially designed for solution-processed individual nanoemitters. This integration would advance the field of cooperative light-matter interactions in pNCs by unlocking cavity-enhanced SF, which is expected to exhibit higher brightness at lower excitation fluences, improved coherence properties, and even SF lasing effects. Overall, CSUPER2 aims to achieve 3 main objectives: (1) to synthesize cubic-shaped pNCs with narrow size-distribution through soft chemistry and ligand-engineering in order to assemble the pNCs into controlled long-range ordered superlattices; (2) to demonstrate SF in the resulting pNC superlattices and investigate in detail the SF fundamental optical properties, such as the spectral signatures, the ultrafast dynamics, the coherence and the photon statistics, using steady-state and time-resolved spectroscopy as well as quantum optics experiments at room and low temperature. The effect of disorder will be precisely analysed in order to assess the number of coherently coupled pNCs contributing to the SF signal; (3) to investigate unexplored areas of cavity-enhanced SF from pNC superlattices, by using a tunable fibered microcavity in order to modify and tune the key element responsible for SF emission, i.e. the dipole-dipole coupling mediated by the vacuum fluctuation of the electromagnetic field. The cavity will thus constitute a new knob to explore the rich physics of SF, and ultimately explore the transition from conventional to SF lasing. To fully exploit the experimental results, the CSUPER2 project will benefit from a strong theoretical support on collective light matter effect. The theoretical studies of the collective emission properties in pNCs superlattices will be done by considering precisely the effect of disorder, along with the effect of the cavity coupling.

The aim of the CHROMIC project is to develop new microfluidic circuits functionalized by mechanofluorochromic materials, i.e. materials whose fluorescence emission is sensitive to mechanical forces, then to use these new devices to measure the force exerted on a single microalgae passing through the circuit and finally to link the force applied in the microfluidic circuit to the increase in the extraction yield of the compounds produced by the microalgae. Our strategy for carrying out this multidisciplinary project is based on 4 stages. Firstly, mechanofluorochromic coatings will be prepared from polydiacetylene-fluorophore dyads, designed to combine versatile synthesis, high sensitivity to mechanical forces, high brightness and biocompatibility. Next, the response of these mechanofluorochromic coatings to friction forces will be calibrated using an AFM coupled to a fluorescence microscope: the tip of the AFM used in contact mode will apply a variable and controlled force, and the variation in the associated fluorescence emission will be recorded simultaneously. In the 3rd step, the microfluidic circuit will be optimised with a parallel architecture enabling a large number of microalgae to be analysed simultaneously, the size of the channels and restrictions will be adapted to study three species of microalgae of interest, and the associated image analysis protocol will be automated. Finally, three species of microalgae varying in size, rigidity and cell wall composition will be studied, and the mechanical force exerted by passage through the microfluidic restrictions, measured by mechanofluorochromism, will be correlated with the extraction yield of the compounds of interest. This project thus proposes a completely new approach to the measurement of forces at the scale of the single cell.

The possibility to integrate low-threshold and miniaturized semiconductor lasers on single chip is at heart of a plethora of applications ranging from optical communication, imaging, lighting to quantum information and data storage. Polariton lasers, making use of exciton-photon strong coupling regime, is one of the most prominent platforms for ultra-low threshold lasing emission. Being a spontaneous emission, this coherent light does not require a population inversion and can take place at a much lower carrier density threshold than the one in conventional photon lasers. Toward a new paradigm of on-chip polariton laser with room temperature operation, low-cost, scalable fabrication and CMOS compatibility, POLAROID project targets three objectives: 1) Optimize solution-based all-inorganic perovskite thin films for robust exciton-photon strong coupling regime at room temperature. 2) Demonstrate polariton lasing from few-micro-size perovskite metasurfaces. 3) Develop opticlly pumped polariton laser with electrical control operating at room temperature.