Ribonucleoprotein particles (RNPs) are made of RNA associated with proteins and play a central role in biological systems (maintenance of cellular homeostasis, establishment of infectious or pathological processes). The identification of the components of these RNPs has exploded over the past decade thanks to the use of high-throughput analytical approaches. The fine characterization of the interaction of the components of these RNPs then requires the analysis of a large number of mutants. While several high-throughput methodologies have been developed for the analysis of RNA mutant libraries, progress has been scarcer on the protein side. To fill this gap, we propose "SURF", a highly multidisciplinary project aiming at developing a new chemistry for the efficient capture of target RNAs on the surface of water-in-oil droplets produced, manipulated, and analyzed at rates of several million per hour in microfluidic devices. Gene libraries encoding mutants of the studied protein fused to a fluorescent domain will be expressed in vitro at a rate of one mutant (produced in large numbers of copies) per droplet. Thus, a mutant able to interact with the target RNA sequence will lead to a relocation of the fluorescent protein on the surface of the droplet, making it easily discriminable from a drop containing a mutant unable to recognize its target (fluorescence remaining diffuse in the droplet). Applied and validated with various biological models, this technology will not only allow to finely characterize the formation of RNPs, but also to reprogram their specificity, and even to identify molecules able to modulate this interaction. Finally, this project will also be an opportunity to explore surfactants made of alternative chemistries having a lower impact on the environment.

Helically coiled filaments are ubiquitous in nature. They are observed at different scales, from molecular to multi-cellular structures, giving them great biological and ecological relevance. When confined under constrained physical space, helical filament leads to the formation of non-linear, multi-stable meandered structures - termed the family of “squeelices”. We have observed helical and “squeelical” behaviors in the filamentous yeast Candida albicans, a benign member of the human microbiota that can turn into one of the most lethal opportunistic fungal pathogens of humans. In this project, we propose an interdisciplinary approach combining genetics, cell biology, biophysics, mechanics and microfluidic tools to provide a comprehensive and mechanistic view of the oscillatory growth of C. albicans hyphae, addressing the biophysical and molecular basis of this phenomenon and deciphering its associated consequences in terms of tissue invasion. We will draw consequences of confined helix models and their possible extensions/refinements for algorithmic decision making in micro-labyrinth navigation. We will actively look for links between tissue invasion and directional decision making abilities to potentially establish a new predictive score for invasion. Overall, we hope to provide a new conceptual toolkit for understanding helical shapes of growing cells and assess whether this generic growth modality represents an evolutionary advantage for invasive filamentous organisms living in complex environments.

The aim of the project 00111001 is to prepare synthetic information-containing macromolecules. Polymers containing sequence-coded information exist in Nature (e.g. DNA) but not in manmade materials. In the present project, digital information will be ‘written’ in synthetic polymers using two monomers defined as 0- and 1-bits. In particular, we will focus on the design of information-storing polymers that contain weak alkoxyamine bonds. Indeed, it was recently found by the applicants that the presence of alkoxyamine linkages in such polymers has important advantages: (i) it speeds-up and facilitates their synthesis, (ii) it greatly simplifies their sequencing by mass spectrometry, and (iii) it renders the formed polymers dynamic and allows potentially sequence manipulation. In this project, three synthetic routes will be considered for preparing alkoxyamine-containing polymers such as poly(alkoxyamine amide)s or poly(alkoxyamine phosphodiester)s. For each route, a wide variety of custom-made monomers will be screened. In particular, tailored nitroxides will be synthesized by the group of Didier Gigmes in Marseille. All polymers will be synthesized by the group of Jean-François Lutz in Strasbourg using iterative solid-phase chemistry. Moreover, automated protocols will be studied in order to prepare long sequence-coded polymers. Another important target of the project will be to ‘read’ the sequences that are encrypted in the polymer chains. For that purpose, sequencing approaches, inspired by methodologies used in genomics and proteomics, will be studied. For instance, the sequences of the formed polymers will be analyzed by tandem mass spectrometry (MS/MS), MS3, and ion mobility spectrometry by Laurence Charles in Marseille but also by high field NMR by Marc-André Delsuc in Strasbourg. New sequencing tools like 2D-FTICR-MS will be also studied jointly by the groups of Delsuc and Charles. Before writing the present application, it was found that alkoxyamine-based sequence-encoded polymers are remarkably easy to sequence due to the presence of alkoxyamine weak links in their chains. For instance, these cleavable bonds enable an excellent “readability” in MS/MS sequencing. In the frame of the project, polymers containing different types of C-ON alkoxyamine bonds will be studied and sequenced. The objective will be to identify optimal structure/readability relationships. Some methods for erasing or scrambling sequence information will be also investigated. Indeed, alkoxyamine-containing polymers are thermolabile and therefore dynamic at elevated temperatures. In addition, photosensitive monomers will be designed. Thus, the digital information encrypted in the chains will be erased by heat or light. The rates and mechanisms of degradation will be studied in details. Overall, the project 00111001 should allow development of a new class of synthetic polymer materials that currently does not exist in manmade technologies.

This project focuses on the fabrication of new polymer thermoelectric materials and to explore how their processing in thin films by crystallization, orientation and soft doping can improve their thermoelectric (TE) properties. It is organized around four tasks: i) the synthesis of new macromolecular architectures of p- and n-type polymers that allow an efficient and controlled doping, ii) to develop alignment methods and soft doping processes to obtain highly structured and oriented conducting polymer films, iii) characterize precisely the structure and orientation of the aligned conducting polymer films by transmission electron microscopy and grazing incidence X-ray diffraction and iv) to determine charge transport and TE properties of the anisotropic polymer films. Thanks to this work, correlations between structure and TE properties will be obtained for model systems and will help obtain a better understanding of the physical mechanisms governing TE properties in highly ordered conducting polymers. Ultimately, this project will generate polymer TE materials with an efficiency ZT=0.1-0.2. The originality of the project stems from the fact that the processing of the conducting polymer films is split in separate and well controlled steps that help fabricate conducting polymer films with high crystallinity and orientation to enhance charge conductivity and TE properties. The proof of concept of this fabrication method of highly oriented, crystalline conducting polymer films has been validated recently by one of the partners of the project. From the material’s point of view, the project will yield new efficient, air-stable p- and n-type conjugated polymers whose doping shall preserve crystalline perfection. Soft-doping from vapor or solution phase as well as electrochemical doping will aim at reaching a controlled intercalation of dopants in the host matrix of the polymer. Most importantly, the correlations between processing, structure and TE properties will be established in order to have a better understanding of the parameters that can enhance TE properties of polymer thin films. This pluridisciplinary project involves four laboratories located in Strasbourg and Tours with highly complementary experties : macromolecular engineering (ICPEES and PCM2E), growth control of polymer thin films and structural investigations (ICS), controled electrochemical doping (PCM2E) and determination of charge transport and thermoelectric properties (GREMAN).

Inspired by the ability of influenza viruses to self-roll on surfaces, we propose a to create artificial photoactive rod particles and investigate their propulsion as rotary motors close to hard and soft interfaces. Self-propulsion results from the interaction between the rod and a light/chemical field gradient normal to the surface, which creates an instability that leads to rolling. Hence, we aim at designing a new class of active particles, which go beyond existing mechanisms (Quinke, Leidenfrost and Fiberboid effects) .The rod geometry will allow us to tune the directionality of the persistent motion and observe dynamics in dilute and concentrated regimes to understand, control and exploit the activity generated by symmetric particles.In line with the groups’ expertise, new rod systems based on photoactive materials (Fe2O3, Ag, TiO2) will be designed by the German Team and studied theoretically and experimentally close to solid interfaces by the French Team.