Electron-Beam Irradiation of the PLLA/CMS/β-TCP Composite Nanofibers Obtained by Electrospinning

PLLA Membranes Enriched with Chitosan/DCPA: Innovative Approach to Bone Tissue Engineering

Bone tissue engineering has been very promising. The use of scaffolds of synthetic and natural materials is an alternative to combine the advantages of both types of materials. This study aimed to evaluate electrospun polymeric matrices of pure PLLA or associated with 5% or 10% of chitosan particles loaded or not with DCPA in bone proliferation and differentiation of periodontal ligament stem cells (PDLSC). The particles and matrices were characterized by scanning electron microscopy. PDLSC were isolated from periodontal ligament fragments of human permanent teeth using the explant technique. Cell proliferation assay (Alamar Blue) was performed from 1 to 21 days of culture in clonogenic medium and Alizarin Red assay was performed after 21 days of culture in osteogenic medium. The data were analyzed using Kruskal-Wallis test, and the comparison between media was given by the Student-Newman-Keuls test (α = 0.05). On days 1 and 7 there were no statistical difference between materials regarding cell proliferation (p>0.05). The materials with 5 and 10% chitosan / DCPA showed greater proliferation than PLLA control on days 14 and 21 and the material with 10% pure chitosan was greater than the control in 21 days. Regarding the alizarin red assay, PLLA 5% chitosan, PLLA 5 and 10% chitosan / DCPA showed a greater degree of mineralization than the control and the PLLA 10% chitosan material, and they were similar to each other. We conclude that PLLA 5 and 10% chitosan / DCPA materials were able to increase both, cell proliferation and differentiation of PDLSC in bone cells. Key words:Chitosan, PLLA, polymeric matrix, electrospinning.

Nanofiber applications in microbial fuel cells for enhanced energy generation: a mini review

Microbial fuel cells (MFCs) represent simple devices that harness the metabolic activities of microorganisms to produce electrical energy from diverse sources such as organic waste and sustainable biomass. Because of their unique advantage to generate sustainable energy, through the employment of biodegradable and repurposed waste materials, the development of MFCs has garnered considerable interest. Critical elements are typically the electrodes and separator. This mini-review article presents a critical assessment of nanofiber technology used as electrodes and separators in MFCs to enhance energy generation. In particular, the review highlights the application of nanofiber webs in each part of MFCs including anodes, cathodes, and membranes and their influence on energy generation. The role of nanofiber technology in this regard is then analysed in detail, focusing on improved electron transfer rate, enhanced biofilm formation, and enhanced durability and stability. In addition, the challenges and opportunities associated with integrating nanofibers into MFCs are discussed, along with suggestions for future research in this field. Significant developments in MFCs over the past decade have led to a several-fold increase in achievable power density, yet further improvements in performance and the exploration of cost-effective materials remain promising areas for further advancement. This review demonstrates the great promise of nanofiber-based electrodes and separators in future applications of MFCs.

Enhancing Mechanical Properties and Flux of Nanofibre Membranes for Water Filtration

Nanofibres have gained attention for their highly porous structure, narrow pore size, and high specific surface area. One of the most efficient techniques for producing nanofibres is electrospinning. These fibres are used in various fields, including water filtration. Although they possess the ability to filter various components, the fibres generally have low mechanical strength, which can mitigate their performance over time. To address this, studies have focused on enhancing nanofibre membrane strength for water filtration. Previous analyses show that the mechanical properties of nanofibre mats can be improved through solvent vapour treatment, thermal treatment, and chemical crosslinking. These treatments promote interfibre bonding, leading to the improvement of mechanical strength. However, excessive treatment alters nanofibre behaviour. Excessive heat exposure reduces interfibre bonding, while too much solvent vapour decreases pore size and mechanical strength. Thus, a comprehensive understanding of these post-treatments is crucial. This review examines post-treatments aiming to increase the mechanical strength of nanofibre mats, discussing their advantages and disadvantages. Understanding these treatments is essential for optimising nanofibre membrane performance in water filtration and other applications.

Electrospun Sulfonatocalix[4]arene Loaded Blended Nanofibers: Process Optimization and In Vitro Studies

In the past decade, electrospun nanofibers made of biodegradable polymers have been used for different biomedical applications due to their flexible features in terms of surface area to volume ratio, pores, and fiber size, as well as their highly tunable surface properties. Recently, interest is growing in the use of supramolecular structures in combination with electrospun nanofibers for the fabrication of bioactive platforms with improved in vitro responses, to be used for innovative therapeutic treatments. Herein, sulfonatocalix[4]arene (SCX4) was synthesized from p-tert-butyl-calix[4]arene and embedded in electrospun nanofibers made of polycaprolactone (PCL) and gelatin (GEL). The supramolecular structure of SCX4 and its efficient entrapment into electrospun fibers was confirmed by NMR spectroscopy and FTIR analysis, respectively. SEM analysis supported via image analysis enabled the investigation of the fiber morphology at the sub-micrometric scale, showing a drastic reduction in fiber diameters in the presence of SCX4: 267 ± 14 nm (without SCX) to 115 ± 5 nm (3% SCX4). Moreover, it was demonstrated that SCX4 significantly contributes to the hydrophilic properties of the fiber surface, as was confirmed by the reduction in contact angles from 54 ± 1.4° to 31 ± 5.5° as the SCX4 amount increased, while no effects on thermal stability were recognized, as was confirmed by TGA analyses. In vitro tests also confirmed that SCX4 is not cytotoxic, but plays a supporting role in L929 interactions, as was validated by the cell viability of PGC15% after 7 days, with respect to the control. These preliminary but promising data suggest their use for the fabrication of innovative platforms able to bind SCX4 to bioactive compounds and molecules for different therapeutic applications, from molecular recognition to controlled drug delivery.

Comparative Analysis of Polymer Composites Produced by FFF and PJM 3D Printing and Electrospinning Technologies for Possible Filter Applications

Three-dimensional printing technologies are mainly used to build objects with complex shapes and geometry, largely prototypes, and thanks to the possibility of building very thin layers of material with small pores, electrospinning technology allows for the creation of structures with filtration properties, in particular very small particles. The combination of these technologies creates new possibilities for building complex-shape composites that have not been comprehensively tested so far. The article describes the results of research on composites manufactured by combining samples prepared with two 3D printing technologies, Fused Filament Fabrication (FFF) and Photo-Curing of Liquid Polymer Resins (PJM) in combination with electrospinning (ES) technology. The surface morphology of composites manufactured from biocompatible materials was investigated using confocal laser scanning microscopy (CLSM) and contact angle measurements, and chemical composition analysis was studied using Fourier transform infrared spectroscopy (FTIR). This approach to creating composites appears to be an alternative to developing research for filtration applications. The article presents basic research illustrating the quality of composites produced by combining two unconventional technologies: 3D printing and electrospinning (ES). The analysis of the research results showed clear differences in the structure of composites produced with the use of various 3D printing technologies. The CLSM analysis showed a much better orientation of the fibers in the MED610 + PAN/gelatin composite, and the measurement of the contact angle and its indirect interpretation also for this composite allows for the conclusion that it will be characterized by a higher value of adhesion force. Moreover, such composites could be used in the future for the construction of filtering devices and in medical applications.

Fibers by Electrospinning and Their Emerging Applications in Bone Tissue Engineering

Bone tissue engineering (BTE) is an optimized approach for bone regeneration to overcome the disadvantages of lacking donors. Biocompatibility, biodegradability, simulation of extracellular matrix (ECM), and excellent mechanical properties are essential characteristics of BTE scaffold, sometimes including drug loading capacity. Electrospinning is a simple technique to prepare fibrous scaffolds because of its efficiency, adaptability, and flexible preparation of electrospinning solution. Recent studies about electrospinning in BTE are summarized in this review. First, we summarized various types of polymers used in electrospinning and methods of electrospinning in recent work. Then, we divided them into three parts according to their main role in BTE, (1) ECM simulation, (2) mechanical support, and (3) drug delivery system.