ABSTRACT
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 (CSF) 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.
ABSTRACT
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 PM0.3, PM0.5, and PM3.0 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.
ABSTRACT
Com o objetivo de desenvolver, caracterizar e avaliar uma superfície microtexturizada de implantes propôs-se a realização deste estudo primeiramente laboratorial, através da Microscopia Eletrônica de Varredura (MEV) e microanálise por Energia de Dispersão (EDS) e, em um segundo estágio in vivo em animais. Para isso, foram fornecidos pela empresa Implacil Materiais Odontológicos (Implantes DeBortoli) 24 implantes cilíndricos, os quais foram divididos em dois grupos: 1 Implantes jateados por TiO; 2 Implantes jateados e microtexturizados por imersão em ácido Fluorídrico. Os resultados demonstraram que na primeira fase os implantes avaliados em MEV do grupo 2 tiveram uma morfologia superficial muito mais uniforme e regular que o grupo 1. Na análise por EDS também o grupo 2 apresentou um melhor resultado, não sendo identificado nenhum tipo de contaminante em suas amostras, diferentemente do grupo 1 o qual tivemos a presença de Alumínio. Na segunda fase em que foram utilizados seis coelhos, que receberam 2 implantes em cada tíbia, foi observado o índice de tecido ósseo corticalizado em contato com a superfície, após oito semanas, tivemos um índice médio de 37,10% no grupo 1 e 58,73% no grupo 2. Em conclusão podemos verificar que é possível controlar físico-quimicamente a microtexturização superficialdos implantes e que isso além de dar uma conformação mais uniforme a superfície, elimina a possibilidade de contaminantes, aumentando o índice de osteointegração e formação de tecido ósseo corticalizado.
In order to develop, characterize and to evaluate a microtextured surface implant proposed to achieve this first laboratory study by Scanning Electron Microscopy (SEM) and microanalysis by energy dispersion (EDS), and a second stage in vivo in animals. For this they were supplied by the company Implacil - Dental Materials (Implants Debortoli) 24 cylindrical implants, which were divided into two groups: 1 - Implants blasted by TiO, 2 - and microtextured blasted implants byimmersion in hydrofluoric acid. The results showed that the first phase the implants evaluated in the SEM group 2 had a surface morphology much more uniform and regular than group 1.The analysis by EDS also in group 2 was better, but no identification of any contaminant in their samples was found, in contrast to group 1 which had the presence of aluminum. In the second phase six rabbits were used receiving 2 implants in each tibia. It was observed the rate of bone corticalization in contact with the surface, after eight weeks, had an average rate of 37.10% in group 1 and 58 73% in group 2. In conclusion we can see that you can control the physical and chemical microtexturization of the surface of implants and that it gives a more uniform forming surface, eliminates the possibility of contaminants, increasing the rate of osseointegration andformation of bone cortical tissue.
