We aim to develop of a new kind of artificial retina containing pixellized architectures of vertically aligned TiO2-based nanotubes, acting as artificial photoreceptors in replacement of degenerated natural ones, when the ‘smart’ neuronal network of retina is partially maintain-ned, as in the case of ca. 50% of blindness in developed countries. The patient number world-wide concerned ranges from 200,000 when considering only a class of rare diseases such as retinitis pigmentosa, to several millions, when including only part of those affected with age-related macular degeneration. This confers a first-order societal interest to this research area. The retinal prosthesis concept with external electrical stimulation of partially-persistent neuronal network, has been implemented so far with implanted parts located both inside and outside of the eyeball, for authorizing information and/or energy transfer to the electro-des. Even if clinical trials validated the concept, with restoration of some visual perception to implanted patients, models tested till now do not allow for a useful vision, i.e. for assuring motion autonomy, face recognition and reading ability (beyond large letter recognition). Our strategy would lead to single implantation of a photoreceptive matrix inside eyeball, with no need of passing a cable through the eye wall. Originality and novelty turn are based on the use of a semi-conductor material made of TiO2 single oxide, nanostructured as pixelli-zed vertically aligned nanotube architecture, obtained by electrochemical anodic synthesis, and carefully modified for transferring its light absorption to the visible range and thus obtaining an architecturized material photoresponsive to visible light stimulation. Prior to the project, the concept of artificial retina based on TiO2 photosensors allowing neuronal stimulation and the feasibility of the controlled and tunable photosensor pixellization, have been validated by the partners. A resolution of at least to 1000 pixels, necessary for restoring useful vision, will be reached by setting a micro-machining process allowing µ-etching by laser ablation of aligned TiO2 nanotube continuous coating, followed by inter-pixel isolating filling obtained by laser-induced local mineralization of a precursor mineral ink, both processes being industrialized by one of the partners. The ease-of-use of both µ-machining processes, associated to their cutting accuracy, to their automatized servo-control and low costs, will allow the symbolic level of 1000 pixels to be reached, while maintaining low implant production costs. The artificial retina device efficiency will be first validated by in vitro electrophysiology over cultured cells and dystrophic retinas. The functional testing will be carried out for assessing sensitivity gain for subretinally implanted blind rats, via the histology of the implant/retina contact and the results of behavior testing. Our results should lead to the consortium enlargement by including a Center for Clinical Investigations, to set the basis for a future clinical testing of this new kind of artificial retina.

Project Summary The ASTRID MATURATIION CARPE DIEM MAGIS project aims at developing new materials of millimeter thickness on a semi-industrial scale to absorb electromagnetic waves in the widest range within the spectral window 1-6 GHz. This project follows the ANR ASTRID CARPE DIEM project in which these materials were studied, and then developed and characterized on the laboratory scale. Applications concern the electromagnetic shielding of electronic components in the civil sphere and the stealth technology in the military field. The proposed work of maturation will first focus on manufacturing of ferromagnetic flakes of various chemical compositions in semi-industrial quantity while respecting the optimal geometric characteristics of these flakes, deduced from the CARPE DIEM project. The next stage is to disperse these flakes in an elastomer matrix using a consistent process of industrialization. The latter must allow to achieve an homogeneous flakes dispersion and maintain, within the matrix, the high degree of flakes orientation obtained on the laboratory scale. Composite plates with decimeter lateral sizes will be then fabricated. Their microwave absorption performance will be determined using free space measurements. In parallel, research activities will be conducted on micrometer-sized flakes on the laboratory scale. Lateral size reduction of flakes results in a decrease of the real effective permittivity of the composite and a change in the permeability spectrum. Interest of these micrometer-sized flakes will be evaluated in terms of microwave absorbing materials. This project is mainly an experimental work including the synthesis of composite materials and their microwave characterizations, consolidated by a modeling activity. For this work, the CARPE DIEM MAGIS project gathers 4 partners : DASSAULT AVIATION, MARION TECHNOLOGIES, PAULSTRA snc and l’Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) with complementary skills.

Many imaging techniques, particularly in environmental transmission electron microscopy (ETEM), generate images with degraded signal-to-noise ratio, contrast and spatio-temporal resolution, which hamper quantification and reliable interpretation of data. Moreover, the extraction of structural information from these images relies on manual acquisition and local structural identification which does not allow statistical analysis of the data and necessarily introduces a human bias carried out at the post-processing stage. The general aim of the ARTEMIA project is to develop a ground-breaking deep learning-based framework for in situ microscopy in liquid and gaseous media allowing the automated, high throughput, real-time acquisition and analysis of ETEM image sequences.Our framework will integrate aberration-corrected in situ ETEM imaging using windowed liquid/gas nanoreactors with denoising and resolution enhancement scheme set up using convolutional neural network (CNN). For model training, datasets consisting of simulated liquid- and gas-phase TEM images will be generated by by atomistic simulations including instrumental noise and imperfections of the microscope optics. In the ARTEMIA project, the CNN models will be applied to the study of two crystalline samples with complementary structural characteristics and electron beam sensitivity, model gold nanoparticles (Au NPs) and microporous zeolite, in reactive gas and/or liquid environments. Our scientific aim will be to gain further mechanistic understanding ofthe growth of model Au NPs in liquid phase and their reactivity in oxidizing and reducing gas environments on one hand and the steaming process of beam-sensitive zeolite on the other hand. The consortium comprises three academic partners (MPQ, LEM, IPCMS) and an EPIC partner (IFPEN) with complementary expertise in liquid and gas ETEM, data science and image processing with special focus on deep learning approaches, atomic modelling and TEM image simulation.

Heterogeneous catalysis, which is involved in about 80% of industrial processes, has a prominent role to play in the quest for clean energy technologies. A major challenge lies in the development of atom-efficient catalysts, i.e. with both maximum efficiency (activity, selectivity, stability) and minimum amount of rare and expensive materials (especially noble metals, which are used in many catalytic processes and in automotive converters). In recent years, due to the development of last-generation electron microscopies, a fast growing interest for so-called “single-atom catalysts”, i.e. catalysts constituted of metals atomically dispersed on a stabilizing support, is observed. Similarly to the “nano” wave which has drastically changed materials science and opened the way to a variety of applications, the additional downscaling may open a new era. As a matter of fact, subnanometric downsizing gives rise to a dramatic change in the electronic properties of metals, which in turn leads to promising catalytic performances. However, as synthesis and characterization of these materials are challenging, the works in this field are still restrained to a limited number of catalytic systems. The UltraCat project aims at the design and investigation of new catalysts based on metals “ultradispersed” in the form of subnanometric particles down to isolated atoms, supported on mesoporous oxides for reactions with high interest for clean-energy-production processes involving hydrogen. The related challenges will be the use of non-noble metals, the tuning of metal loadings so as to increase the catalytic yields without significant decrease of the metal dispersion, and the softening of reactions conditions (lower operating temperatures and pressures). The catalyst preparation methods envisaged in the project are both simple for implementation and original by making use of mixed-oxide and intermetallic alloy chemistry concepts through thermal post-treatments. The first considered reaction is the preferential oxidation of CO in H2 (CO-PROX), which allows ultimate purification of hydrogen for proton-exchange-membrane fuel cells. The second reaction is the hydrogenation of CO2 to methanol, which is a promising way of valorizing anthropogenic CO2 into a high-value platform molecule and energy carrier. Both reactions are known to benefit from a high intimacy between the metal and the support, making the ultradispersion approach relevant. The hydrogen sorption properties of the materials (adsorption, absorption, hydride formation), which are dispersion-dependent and strongly linked to catalytic ones (though often neglected), will be investigated in parallel to catalytic reactions. In order to better understand the dynamic gas-solid interaction phenomena involved in the reactions, and in turn guide the materials conception, the catalytic systems will be investigated by advanced in situ/operando techniques such as aberration-corrected environmental transmission electron microscopy, vibrational spectroscopies (infrared, Raman), and synchrotron X-ray spectroscopies (XAS, XPS). These methods will be complemented by materials and reaction modeling through computer-based simulations using the density functional theory (DFT) within rationalizing and predictive approaches. The UltraCat consortium covers all the above aspects in an interdisciplinary manner (chemistry / physics, catalysis / hydrogen sorption, experiment / theory) while relying on preexisting informal collaborations and promising preliminary results, which should favor the success of this project.