In Vitro Modeling of the Blood-Brain Barrier for the Study of Physiological Conditions and Alzheimer's Disease.

The blood-brain barrier (BBB) is an essential structure for the maintenance of brain homeostasis. Alterations to the BBB are linked with a myriad of pathological conditions and play a significant role in the onset and evolution of neurodegenerative diseases, including Alzheimer's disease. Thus, a deeper understanding of the BBB's structure and function is mandatory for a better knowledge of neurodegenerative disorders and the development of effective therapies. Because studying the BBB in vivo imposes overwhelming difficulties, the in vitro approach remains the main possible way of research. With many in vitro BBB models having been developed over the last years, the main aim of this review is to systematically present the most relevant designs used in neurological research. In the first part of the article, the physiological and structural-functional parameters of the human BBB are detailed. Subsequently, available BBB models are presented in a comparative approach, highlighting their advantages and limitations. Finally, the new perspectives related to the study of Alzheimer's disease with the help of novel devices that mimic the in vivo human BBB milieu gives the paper significant originality.

Feasibility of Producing Core-Shell Filaments through Fused Filament Fabrication.

Fused filament fabrication is a technology of additive manufacturing that uses molten thermoplastics for building parts. Due to the convenient shape of the raw material, a simple filament, the market offers a great variety of materials from simple to blends of compatible materials. However, finding a material with the desired properties can be difficult. Making it in-house or using a material manufacturer can be costly and time-consuming, especially when the optimum blend ratios are unknown or new design perspectives are tested. This paper presents an accessible method of producing core-shell filaments using material extrusion 3D printing. The printed filaments are characterised by a polycarbonate (PC) core and acryl butadiene styrene (ABS) shell with three material ratios. Their performance was investigated through printed samples. Additionally, the material mixing degree was studied by varying the extrusion temperature, nozzle feeding geometry, and layer thickness. The influence of all four factors was evaluated using a graphical representation of the main effects. The results showed that a core-shell filament can be processed using a 3D printer with a dual extrusion configuration and that the mechanical properties of the samples can be improved by varying the PC-ABS ratio. This research provides an accessible method for developing new hybrid filaments with a predesigned structure using a 3D printer.

Improving Fracture Toughness of Tetrafunctional Epoxy with Functionalized 2D Molybdenum Disulfide Nanosheets.

In this work, improved fracture toughness of tetra-functional epoxy polymer was obtained using two-dimensional (2H polytype) molybdenum disulfide (MoS2) nano-platelets as a filler. Simultaneous in-situ exfoliation and functionalization of MoS2 were achieved in the presence of cetyltrimethylammonium bromide (CTAB) via sonication. The aim was to improve the dispersion of MoS2 nanoplatelets in epoxy and enhance the interfacial interaction between nanoplatelets and epoxy matrix. Epoxy nanocomposites with CTAB functionalized MoS2 (f-MoS2) nanoplatelets, ranging in content from 0.1 wt% up to 1 wt%, were fabricated. Modified MoS2 improved the fracture properties (81%) of tetrafunctional epoxy nanocomposites. The flexural strength and compressive strength improved by 64% and 47%, respectively, with 0.25 wt% loading of f-MoS2 nanoplatelets compared to neat epoxy. The addition of f-MoS2 nanoplatelets enhanced the thermomechanical properties of epoxy. This work demonstrated the potential of organically modified MoS2 nanoplatelets for improving the fracture and thermal behavior of tetrafunctional epoxy nanocomposites.