The 2019 coronavirus outbreak and worsening air pollution have triggered the search for manufacturing effective protective masks preventing both particulate matter and biohazard absorption through the respiratory tract. Therefore, the design of advanced filtering textiles combining efficient physical barrier properties with antimicrobial properties is more newsworthy than ever. The objective of this work was to produce a filtering electrospun membrane incorporating a biocidal agent that would offer both optimal filtration efficiency and fast deactivation of entrapped viruses and bacteria. After the eco-friendly electrospinning process, polyvinyl alcohol (PVA) nanofibers were stabilized by crosslinking with 1,2,3,4-butanetetracarboxylic acid (BTCA). To compensate their low mechanical properties, nanofiber membranes with variable grammages were directly electrospun on a meltblown polypropylene (PP) support of 30 g/m². The results demonstrated that nanofibers supported on PP with a grammage of around only 2 g/m² presented the best compromise between filtration efficiencies of PM_0.3, PM_0.5, and PM_3.0 and the pressure drop. The filtering electrospun membranes loaded with benzalkonium chloride (ADBAC) as a biocidal agent were successfully tested against E. coli and S. aureus and against human coronavirus strain HCoV-229E. This new biocidal filter based on electrospun nanofibers supported on PP nonwoven fabric could be a promising solution for personal and collective protection in a pandemic context.

Inkjet printing is a fast, flexible, highly reproducible, and cost effective manufacturing technology that allows the production of both simple and complex 3D geometries from Computer-Aided Design (CAD) data without the requirement of extra tooling. In this work, we studied the influence of different binders (polyvinyl alcohol (PVA), polyvinyl acetate (PVAc) and arabic gum) on the mechanical and porosities properties of ceramics alumina (Al2O3) parts manufactured via 3D inkjet printing. Green specimens were printed using Al2O3 powder as a precursor material and PVA, PVAc and arabic gum suspensions as binder. Green samples were sintered at 1200–1500 °C for 1 h. The microstructure and porosity of sintered samples were evaluated by scanning electron microscope (SEM). Apparent porosity, apparent density and water absorption were measured and the influence of the binders on the compressive behavior was investigated. Results showed that the compositions with best geometric format and mechanical strength were those with polyvinyl alcohol and arabic gum. These specimens showed superior values of apparent densities, lowest porosities, presenting pore size of ≈12 μm, and compression strength of ≈25 MPa.

The dura mater, the furthest and strongest layer of the meninges, is crucial for protecting the brain and spinal cord. Its biomechanical behavior is vital, as any alterations can compromise biological functions. In recent decades, interest in the dura mater has increased due to the need for hermetic closure of dural defects prompting the development of several substitutes. Collagen-based dural substitutes are common commercial options, but they lack the complex biological and structural elements of the native dura mater, impacting regeneration and potentially causing complications like wound/postoperative infection and cerebrospinal fluid leakage. To face this issue, recent tissue engineering approaches focus on creating biomimetic dura mater substitutes. The objective of this review is to discuss whether mimicking the mechanical properties of native tissue or ensuring high biocompatibility and bioactivity is more critical in developing effective dural substitutes, or if both aspects should be systematically linked. After a brief description of the properties and architecture of the native cranial dura, we describe the advantages and limitations of biomimetic dura mater substitutes to better understand their relevance. In particular, we consider biomechanical properties' impact on dura repair's effectiveness. Finally, the obstacles and perspectives for developing the ideal dural substitute are explored.

In this study, hydroxyapatite (HAp) was mixed with pine oil (PO) to coat Co-15Cr-15W-10Ni alloy via brushing method and subsequent heat treatment. Four different surfaces were coated to assess the influence of the roughness on wettability properties and interaction between substrate and coating. The coated substrates were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), profilometer analysis, wettability and scratch resistance. The contact angle of water on the metal implant surfaces was much higher (68°C) than that of PO (23°), allowing a more homogeneous coating process when PO was used for HAp suspension. The effect of heat treatment on the metal-coating bonding strength also was evaluated. Thermal and chemical analyzes corroborated that after heat treatment there was no evidence of PO and only phases related to pure hydroxyapatite were detected. An interaction between substrate and coating was obtained for all surface morphologies, however, the smoother surfaces showed better adhesiveness than the rougher ones. This novel HAp coating method is expected to be suitable for medical applications due to its high potential as alternative to complex and expensive conventional coating methods.

Bioactive glass (BG) is a promising material known for its osteogenic, osteoinductive, antimicrobial, and angiogenic properties. For this reason, melt-quench-derived BG powders embedded into composite electrospun poly(ε-caprolactone) (PCL) mats represent an interesting option for the fabrication of bioactive scaffolds. However, incorporating BG into nano-/micro-fibers remains challenging. Our research focused on integrating two BG compositions into the mat structure: 45S5 and 45S5_MS (the former being a well-known, commercially available BG composition, and the latter a magnesium- and strontium-enriched composition based on 45S5). Both BG types were added at concentrations of 10 wt.% and 20 wt.%. A careful grinding process enabled effective dispersion of BG into a PCL solution, resulting in fibers ranging from 500 nm to 2 µm in diameter. The mats’ mechanical properties were not hindered by the inclusion of BG powder within the fibrous structure. Furthermore, our results indicate that BG powders were successfully incorporated into the scaffolds, not only preserving their properties but potentially enhancing their biological performance compared to unloaded PCL electrospun scaffolds. Our findings indicate proper cell differentiation and proliferation, supporting the potential of these devices for tissue regeneration applications.