Dr. Cécilia Ménard-Moyon  (CNRS, Immunology, Immunopathology and Therapeutic Chemistry, UPR 3572, University of Strasbourg)

Résumé :

The relatively low-cost production of graphene oxide (GO) and its dispersibility in various solvents,
including water, combined with its tunable surface chemistry, make GO an attractive building block to
design multifunctional materials. There are many applications for which it is fundamental to preserve
the intrinsic properties of GO, for instance in the biomedical field. As a consequence, the derivatization
of GO to impart novel properties has to be well controlled and the characterization of the functionalized
samples thoroughly done. Despite the great progress in the functionalization of GO, its chemistry is not
always well controlled and not fully understood.[1] In this context, I will explain some strategies for the
functionalization of GO through the selective derivatization of the epoxides and hydroxyl groups without
alteration of its properties and with biomedical perspectives for anticancer therapy.[2,3] I will also
present how the incorporation of carbon nanomaterials, such as carbon nanotubes and GO, in hydrogels
formed by the self-assembly of aromatic amino acid derivatives can control drug release.[4,5]
[1] Guo S, Garaj S, Bianco A, Ménard-Moyon C, Nat. Rev. Phys., 4 (2022) 247.
[2] Guo S, Nishina Y, Bianco A, Ménard-Moyon C, Angew. Chem. Int. Ed. Engl., 59 (2020) 1542.
[3] Guo S, Song Z, Ji DK, Reina G, Fauny JD, Nishina Y, Ménard-Moyon C, Bianco A, Pharmaceutics, 14 (2022) 1365.
[4] Guilbaud-Chéreau C, Dinesh B, Schurhammer R, Collin D, Bianco A, Ménard-Moyon C, ACS Appl. Mater.
Interfaces, 11 (2019) 13147.
[5] Xiang S, Guilbaud-Chéreau C, Hoschtettler P, Stefan L, Bianco A, Ménard-Moyon C, Int. J. Biol. Macromol., 255
(2024) 127919.

Orateur : Rupert Huber (Department of Physics and Regensburg Center for Ultrafast Nanoscopy (RUN)
University of Regensburg)

Résumé : The carrier wave of light can drive electrons through solids on time scales faster than a cycle of light. This ‘lightwave electronics’ concept opens a fascinating coherent quantum world full of promise for future quantum technologies. We will discuss prominent examples of lightwave-driven dynamics in solid-state quantum materials, ranging from Bloch oscillations via topologically non-trivial electron trajectories to optical band-structure engineering and attoclocking of Bloch electrons. We also take slow-motion movies of single molecules and atomic defects and observe the quantum flow of electrons with the first all-optical subcycle microscope reaching atomic resolution. Our results offer a radically new way of watching and controlling elementary dynamics in nature or steer chemical reactions, on their intrinsic spatio-temporal scales.

Philippe POULIGUEN (Agence Innovation Defense (AID)

L’exposé comportera les présentations :

• de l’AID
• du domaine Ondes Acoustiques et Radioélectriques (en focalisant sur la partie radioélectrique)
• des outils de soutien à la recherche

Résumé :

Organic semiconductors  are remarkable carbon-based materials that combine novel  semiconducting optoelectronic properties with simple processing.  They can be used to make printed and flexible electronics,  and their properties (e.g.  colour) can be tuned  by changing their chemical structure.  Organic light-emitting diodes (OLEDs) are compact visible light sources that are now found across the world in mobile phone displays and televisions.  This talk will give an introduction to organic semiconductors and optoelectronic devices made from them.

It will then explore two emerging fields of application. The first is photodynamic therapy (PDT).  In PDT light in combination with a light-activated chemical leads to the generation of reactive oxygen species.  OLEDs are very attractive light sources for PDT because they emit over an area, are thin and potentially flexible.   We have shown that PDT with OLEDs can kill skin cancer, parasites and bacteria.   Another emerging application is in visible light communication (or Li-Fi) in which light is modulated to encode information to supplement Wi-Fi.  Finally a new organic optoelectronic device – a laser electrically driven by an OLED will be presented.

Orateur : Niels de Jonge (Bruker AXS, Karlsruhe, Germany.)

Résumé : Liquid phase electron microscopy (LP-EM) is capable of studying a wide range of sample from materials science, for example, nanoparticles, and biological samples such as proteins and cells in liquid [1]. Different experimental systems are presented, and the physics of image formation is discussed. The obtained spatial resolution is typically limited by ration damage [2], but damage mitigation by at least an order of magnitude is possible [3]. The full scale application of LP-EM for soft matter research still faces several challenges but strategies to to overcome them are emerging, so that time-resolved imaging of processes in soft-matter samples seems within reach [4].  

Employing the unique capabilities of LP-EM, we studied the spatial organization of the membrane protein HER2 in cancer cells. This protein is a member of the epidermal growth factor receptors (EGFRs), and plays an important role in breast cancer aggressiveness and progression. Breast cancer cells were examined by labeling HER2 proteins with quantum dot (QD) nanoparticles for correlative fluorescence microscopy and LP-EM [5]. We discovered a small sub-population of cancer cells with a different response to a prescription drug indicating a possible relevance for studying the role of cancer cell heterogeneity in the development of drug resistance, and studied biopsie samples from patients [6].

LP-EM was also used to directly image dynamic self-assembly behavior of nanoparticles in liquid from which the interplay between nanoparticle shape, ligand shell structure, and substrate–nanoparticle interactions was studied [7].

References:

• 1.    Nat Nanotechnol 6, 695 (2011).
• 2.    Nat Rev Mater 4, 61 (2019).
• 3.    Nano Lett 18, 7435 (2018).
• 4.    Adv Mater 32, 2001582 (2020).
• 5.    Sci Adv 1, e1500165 (2015).
• 6.    Mol Med 25, 42 (2019).
• 7.    Adv Mater 34, 2109093 (2022).

Katja HEINZE  (Department of Chemistry, Johannes Gutenberg University)

Abstract