The project aims at developing the picosecond ultrasonic technique (PU) as a non-contact and non-invasive mean to perform quantitative non-invasive imaging of single cell adhesion on a functionalized biomaterial surface. The adhesion of living cells on biocompatible substrates plays a crucial role in tissue response to implanted devices and tissue regeneration, and influences cell proliferation and differentiation. In order to optimize implants, it is therefore vital to understand and control cell adhesion. Yet, measuring non-invasively adhesive properties of biological cells at a sub-micron scale remains a challenge. None of the existing techniques can provide such quantitative knowledge. In our experimental situation, the cell will adhere on one side of a thin functionalized titanium film, and the laser will be focused on the other side. Absorption of femtosecond laser pulses will launch GHz acoustic waves in the film. Thus, using PU as a non-contact and non-invasive mean, we will measure the acoustic reflection coefficient at the biomaterial-cell interface directly. This acoustic reflection coefficient can be merely converted into an interfacial stiffness, representative of the cell-biomaterial bonding state. In addition, using the fast imaging set-up we have recently patented, measurement time has been reduced by a factor 10000. Introduction of this imaging device in the new set-up will allow the acquisition of adhesion maps in a convenient duration with a sub-micron resolution. The proposed technique is thus unique since it is non-invasive, yields direct mechanical quantification of the cell-biomaterial contact, and allows imaging with a submicron resolution. To put the project on solid physical grounds, we first analyze the well-controlled chemically-induced adhesion of biomimetic objects. We consider model polymer microcapsules to calibrate the experiments, before moving on to cell-mediated adhesion. This grounding stage is performed before the beginning of the project supported by ANR, with another funding (PEPS CNRS/Idex Bordeaux). Regarding the ANR project itself, in a secured step by step approach, we will start with the adhesion of model cells. Monocytes will be considered first since their size, shape and uniform adhesion resembles that of microcapsules. Their small size will allow performing 1D scans along a line across single cell adhesion area with simple modifications of the usual set-up. Then oscteoclast cells will be considered as more advanced model cells. Their adhesion is mediated through an adhesion belt of podosomes yielding a non-homogeneous annular adhesion at the periphery of the cell-material interface. For quantitative imaging purpose we will perform the adaptation of a new imaging device to map the acoustic reflection coefficient in 2D. Notably, femtosecond laser beams will be introduced in a modified commercial microscope allowing simultaneous fluorescent imaging. The comparison of the 2D opto-acoustic images of the osteoclasts with qualitative fluorescent images should prove the ability of our technique to measure and image heterogeneous cell adhesion. We will then be able to achieve the quantitative imaging of highly heterogeneous cell adhesion at a sub-cell scale. Human osteoblast cells will be grafted on titanium surfaces functionalized with different peptide concentrations. Both the variation of the adhesion and of the cell structure at the focal points of adhesion will be acoustically imaged with a sub-micron resolution. These quantitative measurements will be of a great interest to understand cell-materials interactions. They should notably allow optimizing the density of peptides to be grafted on the biomaterial surface. Moreover, measurements of both cell adhesion and compressibility should allow analysing the cytoskeleton modification and its correlation to cell signalling pathways.

Acoustic Metamaterials constitute a new and promising generation of materials whose unconventional characteristics, based on "exotic" values of their acoustic index (from 0 to infinity, imaginary, even negative), open the way to many advanced applications such that wave-field spatial control (for high-resolution imaging and beamforming), ultra-absorption and cloaking (for insulation and stealth). Among all classes of metamaterials, the locally resonant metamaterials take advantage of low-frequency resonances of "small" inclusions. Thanks to those local resonators these metamaterials allow the full control of long-waves while keeping a small size (sometimes very small), giving rise to the name of "sub-wavelength" metamaterials. At that time, there is a great deal of interest for applications with those acoustic materials especially for insulation in the audible domain and for stealth in underwater acoustics. Also, but with probably a lower societal and strategic pressure, the issues for ultrasonic instrumentation and imaging are potentially significant. Nevertheless acoustic metamaterials are still mostly at the stage of conceptual objects of laboratory. The route of soft-matter techniques opens up many ways of designing and fabricating new materials thanks to their great variety of processes and to the physical/chemical properties of the involved constituents (polymers for instance). Turning to good account our recent successful developments of macro-porous resonators (polymeric foam micro-beads), which are a key-element for acoustic metamaterials, we are at the stage where we can envisage the making of many different types of metamaterial-based devices relying on a large range of index-values (now experimentally available). This proposal is a strongly multi-disciplinary project between three labs in Bordeaux, expert in wave-physics, soft-matter and microfluidics. The consortium has more than 5 years of experience in joint-research on the topic of soft-metamaterials. This long collaboration coupled to the geographical proximity and the developed complementary skills is a key-point for challenging both the material and the acoustic aspects of the project. The Material challenge is to develop a new class of acoustic coatings based on the metamaterials concept, which are easily processable and up-scalable. First the meta-matter can be a fluid-based dispersion like paint and turned afterwards into solid-but-soft coating upon polymerization over a large variety of surfaces. Second, the meta-coating can be structured by using soft-lithography and shaped by molding. In that project the possibilities for the resonators synthesis and their structuring into a metamaterial-device are quite vast. The Wave-Physics challenge concerns the design and the experimental proof of targeted functions of several demonstrators. The chosen functions, in connection with further breakthrough technologies, deals with first: sub-wavelength absorption in the context of insulation and stealth; and second: wave-field spatial control for beamforming/front-shaping and cloaking. The flow scheme of BRENNUS is the following: 1. Chemistry and synthesis of micro-resonators according to some criterions (size, shape, high calibration, surface treatment, mass production...) and formulation of the host matrix; 2. Structuring and shaping metamaterials using soft-matter techniques in order to achieve paint-like raw metamaterial, flexible coatings and molded structures; 3. Realization of three types of demonstrators: a. Sub-wavelength meta-coating for sound insulation and stealth b. Transducer caps for beamforming in ultrasonics c. Anisotropic meta-layers for cloaking structures

The objective of this academic proposal is to initiate a technological breakthrough by developing a new class of locally-resonant passive acoustic materials for stealth and discretion in underwater acoustics. These metamaterials are synthesized from polymer engineering and involve strong resonant multiple-scattering phenomena within the medium. The main focus of this project is the engineering of sound/noise control in marine environment for the military and civilian areas. The potentialities of these new materials are: increasing sound absorption levels; the possible reduction of thickness of anechoic or masking coatings; a good compatibility with the industrial constraints of manufacture and use. This proposal is a strongly multidisciplinary project between three CNRS laboratories from the Bordeaux campus (experts in wave-physics, soft-matter and microfluidics techniques) and a major industrial group specialized in naval defence. The academic partners have more than 7 years of joint research on the topic of metamaterials (design and manufacturing) and DCNS has recently had a CIFRE/DGA action with one of them. This long collaboration coupled with a geographical proximity and a complementarity of skills up to the industrial level, is a key point to meet the materials and acoustics challenges of the project. The materials challenge. These inclusion-type materials will incorporate sub-millimetric porous micro-resonators (made by emulsions or microfluidics) dispersed in an elastomer matrix adapted to the marine environment. Using "dense" and "resonant" inclusions must make it possible to address two major challenges for better performance of the boat-hull coverings: resistance to hydrostatic pressures during immersion; higher absorption properties due to the resonant multiple scattering. The wave physics challenge concerns the modeling and the experimental proof of the functions and characteristics sought for the synthesized subwavelength materials/structures. An important phase for ultrasonic characterization under mechanical loading of the laboratory samples will indicate the performance of the latter, in particular in terms of absorption. Contextualized experiments will be conducted to predict the anechoic/masking power of the laboratory materials, as well as acoustic measurements on metric panels placed in a pressurized tank. The industrial challenge seeks to take into account at the project outset, a number of manufacturing and use constraints that cannot be avoided by the industrial over the medium to long terms. This is why the soft-matter techniques that are easily-to-be-industrialized techniques, and the account for the hydrostatic pressure are two key elements at the heart of this exploratory-research project for naval engineering. The synoptic operational overview of PANAMA is as follows. 1. Definition of the resonant inclusion media (acoustic design) according to the targeted specifications (absorption level, frequency range, static/dynamic impedance, static loading). 2. Chemistry and synthesis of porous micro-resonators according to certain criteria: size, shape, calibration, controlled polydispersity, mass production. Incorporation of the objects in an elastomer matrix. 3. Acoustic experiments/tests (in laboratory: under loading in open air; in a conventional acoustic water-tank at atmospheric pressure; in a specialized laboratory: in a pressurized tank).

MOSAIC (MOisture Simulation and Assessment In Civil engineering) is an Initial Training Network (ITN) program to train future scientists in the field of sustainable construction materials. The MOSAIC proposal was already submitted in the ITN (ETN) Marie Sklodowska Curie Action call, the last evaluation score 87.4%. The MRSEI grant will give us means to make major changes for challenging the 2020’s ITN call. The project MOSAIC focuses on various materials, procedures and applications in the field of sustainable construction. An original, multidisciplinary and complementary approach addresses the presence of moisture, its evaluation and the role it plays in damage. Structures made of wood, concrete or brick and stone masonry will all be considered. Issues linked to determining and measuring moisture, its distribution within the structure and its evolution over time will be addressed So far the project was relying on an existing Technical Committee from RILEM (a scientific and technical international association that develops knowledge on materials properties and structural performance). The network is supported by academic and non academic partner organizations, who come from different socioeconomic backgrounds (owners, research and technical centers, industries and SME on materials, diagnosis and consulting), and who are working on the issue of heritage conservation and, building sustainability. According to the previous evaluation of the project, we need to organize the partnership differently while refocusing the project. The MRSEI will help us to reach this objective. The objective of the ITN is to train 15 doctoral students with a 360-degree perspective. By virtue of the partnership trans-disciplinary culture, they will be able to push back the present borders between different materials and techniques. The project is structured around scientific work packages aiming to achieve progress on development of new techniques and methodologies for moisture assessment; improvement of interpretation for evaluation of moisture; standardization of practice applications linked to moisture assessment. The establishment of a data exchange platform to support future scientific progress is also planned. Since an ITN aims as the training of future scientists a work package will be entirely devoted to this task structuring schools, and secondment to allow doctoral students to grow up to an original and attractive employment profile, capable of working in an international landscape. A last work package will deploy modern, original resources in order to communicate disseminate the advances and findings to all echelons of society. The project proposed for this MRSEI call is to favor physical meetings allowing brainstorming and more common writing, as well as to accede to external helps from experts. The initial project will be rebuilt by identifying the roles and involvement needed (based on a partnership already partly identified), as well as the structure of our project.