Institut Français du Textile et de l'Habillement

Si le système universitaire libanais – un des plus anciens du monde arabe et des plus réputés – a survécu au conflit civil qui a déchiré le pays entre 1975-1989, il est aujourd’hui plus que jamais menacé d’effondrement. La crise économique et politique de 2019, la dévaluation de la livre libanaise, l’explosion du 4 août 2020 et la crise sanitaire liée à la pandémie de la Covid 19, fragilisent les fondements de l’enseignement supérieur. Comment mesurer l’impact de ces crises sur les institutions académiques ? Quelles conséquences sur l’avenir de l’enseignement supérieur et la recherche dans un Liban en faillite ? Quelles adaptations et contournements les universités mettent en place pour endiguer l’effondrement ? Tel est le propos de cet article qui se base sur deux enquêtes de terrain effectuées en octobre 2020 et avril 2021 à Beyrouth.

By collagen skin (CS) we mean a material with only collagen fibres in a natural animal skin. Following continuous research of collagen biochemistry, CS shows its superiority in various applications such as leather, wound dressing and absorbing materials. This study discovered the water-induced shape memory effect of CS and exploited the corresponding mechanisms in terms of its molecular and morphological structure. It is revealed that CS can completely fix into a temporary shape and retain a high shape recovery ratio (>90%) under repeatable memory cycles. The reversible cleavage and re-formation of interpeptide hydrogen bonds can work as a "switch" to trigger the shape deformation while peptide chains together with cross-links within collagen work as a "netpoint" for shape recovery. Such water-responsive adaptable mechanical behaviour (a switchable modulus) allows CS to be either used as a robotic handle for loading or as a flexible material for covering. This discovery will provide new opportunities and guidance in emerging research areas such as shape memory devices, biomimetic actuators and artificial skins as well as the physiological function of an animal skin.

Spider silks are attractive biopolymers due to their excellent mechanical properties and biomimetic potential. To optimize the electrostatic interaction for lysosomal drug delivery, a spider-eggcase-silk protein was genetically engineered using 5× His Tag with a tailor-made isoelectric point of 4.8. By a facile HFIP-on-oil method, silk spheres were assembled as rapidly as 10 s. After the post-treatment of ethanol, silk spheres were determined with an improved compressive modulus by AFM indentation. Under incubation of silk spheres in a Doxorubicin solution, a maximum of 35% loading and average of 30% loading efficiency were determined. In the cytotoxicity experiment, silk spheres exhibited intrinsic biocompatibility and showed good control of the loaded drug in the neutral PBS solution. Significantly, by 96 h, the accumulative drug release at pH 4.5 was approximately 4.5-fold higher than that at pH 7.4. By conducting the platelet adhesion and hemolysis assay, Doxorubicin-loaded silk spheres exhibited good hemocompatibility. To further demonstrate this release behavior, within 24 h, Doxorubicin-loaded silk spheres were efficiently delivered to lysosomes and then released the payload to the nuclei of Hela cells.

An easily manipulated protocol for patterning of MXenes on commercial printing paper for planar micro-supercapacitors is reported, with which the fabricated devices can acquire a maximal areal capacitance of 27.29 mF cm−2, achieving at least 460% enhancement compared to the value of advanced carbon-based planar MSCs (0.1–6 mF cm−2).