Extraction, characterization and properties evaluation of pineapple leaf fibers from Azores pineapple.

Pineapple leaves can provide competitive and high-quality fibers for textile purposes. Despite pineapple being cultivated in the Portugues islands there is still a technology gap for the extraction and treatment of Pineapple Leaf Fibers (PALF) in Europe. Since Azorean Pineapple differs significantly from other plants in the bromeliad family, the properties and characterization of its leaf fibers were explored for the first time. Long fibers have been extracted by hand scraping and compared to biological retting at 25 °C for different time periods. It was explored the properties of PALF from plants of different ages (11- and 18-months) and from different zones of the leaves (beginning, middle, and tip). Physical-mechanical properties of Azores PALF were determined, including diameter, linear density, strength, Young's modulus, and elongation at break and characterized by ATR-FTIR, XRD, TGA/DTG, and FESEM to understand their chemical and morphological characteristics. While slight differences were observed between different ages, variations in physical-mechanical properties were notable among fibers extracted from different leaf positions. Extraction of Azores PALF through 25 °C biological retting for 14 days effectively eliminated non-fibrous matter and produced the thinnest and strongest fibers. These fibers ranged between 34.9 and 168.3 µm in diameter, 1.39 and 7.07 tex in linear mass density, 37-993 MPa in tensile strength, 1.0-3.9 % in elongation at break, and 2.4-21.8 GPa in Young's modulus.

Localized Therapeutic Approaches Based on Micro/Nanofibers for Cancer Treatment.

Cancer remains one of the most challenging health problems worldwide, and localized therapeutic approaches based on micro/nanofibers have shown potential for its treatment. Micro/nanofibers offer several advantages as a drug delivery system, such as high surface area, tunable pore size, and sustained release properties, which can improve drug efficacy and reduce side effects. In addition, functionalization of these fibers with nanoparticles can enhance their targeting and therapeutic capabilities. Localized delivery of drugs and/or other therapeutic agents via micro/nanofibers can also help to overcome the limitations of systemic administration, such as poor bioavailability and off-target effects. Several studies have shown promising results in preclinical models of cancer, including inhibition of tumor growth and improved survival rates. However, more research is needed to overcome technical and regulatory challenges to bring these approaches to clinical use. Localized therapeutic approaches based on micro/nanofibers hold great promise for the future of cancer treatment, providing a targeted, effective, and minimally invasive alternative to traditional treatments. The main focus of this review is to explore the current treatments utilizing micro/nanofibers, as well as localized drug delivery systems that rely on fibrous structures to deliver and release drugs for the treatment of cancer in a specific area.

Wetspun Polymeric Fibrous Systems as Potential Scaffolds for Tendon and Ligament Repair, Healing and Regeneration.

Tendon and ligament traumatic injuries are among the most common diagnosed musculoskeletal problems. Such injuries limit joint mobility, reduce musculoskeletal performance, and most importantly, lower people's comfort. Currently, there are various treatments that are used to treat this type of injury, from surgical to conservative treatments. However, they're not entirely effective, as reinjures are frequent and, in some cases, fail to re-establish the lost functionality. Tissue engineering (TE) approaches aim to overcome these disadvantages by stimulating the regeneration and formation of artificial structures that resemble the original tissue. Fabrication and design of artificial fibrous scaffolds with tailored mechanical properties are crucial for restoring the mechanical function of the tissues. Recently, polymeric nanofibers produced by wetspinning have been largely investigated to mimic, repair, and replace the damaged tissue. Wetspun fibrous structures are extensively used due to their exceptional properties, such as the ability to mimic the native tissue, their biodegradability and biocompatibility, and good mechanical properties. In this review, the tendon and ligament structure and biomechanics are presented. Then, promising wetspun multifunctional fibrous structures based on biopolymers, more specifically polyhydroxyalkanoates (PHA), polycaprolactone (PCL), and polyethylenes, will be discussed, as well as reinforcing agents such as cellulose nanocrystals (CNC), nanoparticles, and growth factors.

Protective Multifunctional Fibrous Systems Based on Natural Fibers and Metal Oxide Nanoparticles.

In recent years, an unprecedented increase in the development of products and technologies to protect the human being has been observed. Now, more than ever, the world population is exposed to several threats, harmful to their well-being and health. Chemical and biological hazardous agents stand out as one of the biggest threats, not only for the military forces, but also for the civilians. Consequently, it's essential to develop personal protective systems that are able to protect their user, not only passively, but actively, being able to detect, adsorb, degrade and decontaminate pesticides, pollutants, microorganisms and most importantly: chemical/biological warfare agents. One recent strategy for the development of active fibrous structures with improved functions and new properties is their functionalization with nanoparticles (NPs), especially metal oxides. Although their known effectiveness in the decomposition of harmful agents, the NPs could also include other functionalities in the same structure using low quantities of material, without adding extra weight, which is of huge importance for a soldier in the battlefield. The use of natural fibers as the substrate is also very interesting, since this material is a much sustainable alternative when compared to synthetic ones, also providing excellent properties.

The Potential of Graphene Nanoplatelets in the Development of Smart and Multifunctional Ecocomposites.

Graphene and its derivatives have shown outstanding potential in many fields and textile/composites industry are not an exception. Giving their extraordinary properties, Graphene Nanoplatelets (GNPs) are excellent candidates for providing new functionalities to fibers and composites. In this work, natural fabrics (flax) were functionalized with chitosan (CS) based polymeric formulations of GNPs to develop fibrous systems with electrical properties as well as other functionalities. One of the greatest disadvantages of using carbon-based materials for fabrics' impregnation is their difficult dispersion. Therefore, several polymers were used as matrices, binding and dispersive agents including chitosan, polyethylene glycol (PEG), and glycerol. All the systems were characterized using several techniques that demonstrated the presence and incorporation of the GNPs onto the composites. Besides their characterization, considering their use as smart materials for monitoring and sensing applications, electrical properties were also evaluated. The highest value obtained for electrical conductivity was 0.04 S m-1 using 2% of GNPs. Furthermore, piezoresistive behavior was observed with Gauge Factor (GF) of 1.89 using 0.5% GNPs. Additionally, UV (ultraviolet) protection ability and hydrophobicity were analyzed, confirming the multifunctional behavior of the developed systems extending their potential of application in several areas.

Role of NMDA receptors in the trigeminal pathway, and the modulatory effect of magnesium in a model of rat temporomandibular joint arthritis.

Temporomandibular joint (TMJ) arthritis is a common cause of orofacial pain. In the present study, the modulatory effects of N-methyl-d-aspartate receptors (NMDA-Rs) and magnesium were investigated in TMJ arthritis hypernociception. Male Wistar rats received an intra-articular injection of carrageenan (Cg) in the TMJ, and mechanical hypernociception was measured. The NMDA-R antagonist, MK-801, and magnesium chloride (MgCl2 ) were administered before arthritis induction. Magnesium deficiency was promoted by feeding rats a synthetic magnesium-free diet for 9 d before injection of Cg. The Cg induced mechanical hypernociception that lasted for 120 h. MK-801 inhibited this hypernociceptive state. MgCl2 pretreatment prevented Cg-induced hypernociception and altered the nociceptive threshold in the absence of Cg. Magnesium deficiency increased hypernociception and induced spontaneous hypernociceptive behavior. TMJ arthritis increased the expression of mRNA for all NMDA-R subunits and immunostaining of phosphorylated NR1 (phospho-NR1). MgCl2 inhibited expression of NR2B mRNA and phospho-NR1 immunostaining and increased expression of NR3 mRNA. Magnesium deficiency increased expression of both NR1 and NR3 mRNAs and phospho-NR1 immunostaining in the trigeminal subnucleus caudalis. We found that magnesium modulates nociceptive behavior and induces NMDA-R subunit rearrangement in the subnucleus caudalis. The present results may lead to a better understanding of central processing in the nociceptive trigeminal pathway and the development of new approaches to treat orofacial pain with a TMJ origin.