Since the SARS-CoV-2 pandemic, the interest in applying nanofibers t air filtration and personal protective equipment has grown significantly. Due to their morphological and structural properties, nanofibers have potential applications for air filtration in masks and air filters. However, most nanofiber membrane materials used for these purposes are generally non-degradable materials, which can contribute to the disposal of plastic waste into the environment. Hence, this work aims to produce polyvinyl alcohol (PVA) and chitosan (CS) biodegradable nanofibers with controlled morphology and structure via electrospinning. An experimental design was used to investigate the effects of the PVA|CS ratio and concentration on the properties of the electrospinning compositions and electrospun nanofiber mat. The electrospinning parameters were constant for all experiments: Voltage of 20 kV, a feed rate of 0.5 mL·h⁻¹, and a distance of 10 cm between the needle and a drum collector. CS proved to be an efficient adjuvant to the PVA’s electrospinning, obtaining a wide range of nanofiber diameters. Furthermore, 6.0% PVA and 1% CS were the best compositions after optimization with the response surface methodology, with a mean fiber diameter of 204 nm. The addition of biocide agents using the optimized condition was also investigated, using surfactants, citric acid, and pure and encapsulated essential oils of Lippia sidoides. Pure oil improved the material without enlarging the nanofiber sizes compared to the other additives. The nanofiber membranes produced have the potential to be used in air filtration or wound-dressing applications where biocidal activity is needed.

Disposable surgical masks have emerged as a solution to the increasing demand for protection against fine/ultrafine particulate matter. This was prompted by the SARS-CoV-2 pandemic and the escalating levels of air pollution in major cities. However, as non-degradable polymers, surgical masks are discarded into the environment and become pollutants. This study produced biodegradable nanofibers via electrospinning, using polyvinyl alcohol (PVA) and chitosan (CS) as substitutes for traditional polymers in a three-layer commercial surgical mask (CSM). Electrospinning production parameters were modeled using response surface methodology and optimized using the desirability method. Then, the air filtration properties, including quality factor (Q_f), collection efficiency (η), pressure drop (ΔP) and permeability (K₁), were compared with CSM. The main objective was to produce electrospun mats with filtration of fine/ultrafine particles similar to those obtained for the CSM (η: 42.84–67.80% and ΔP: 29.3–32.2 Pa). Subtle variations in production parameters significantly affected the material, with the electric field being the most relevant parameter. The optimized samples OEV(↓K₁) and OEV(↓Q_f) presented the highest η values (96.27 and 96.58%, respectively), matching the N95 filtration efficiency and complying with international regulations. Their optimal experimental sets were, respectively, 25.01 and 23.39 kV of tension applied for the electrical field, 0.92 and 1.17 mL h⁻¹ of flow rate, and 24.87 and 27.93 min of production time. Notably, nanofibers were more effective than the CSM in capturing particles close to the nanoscale range, such as airborne viruses and fine/ultrafine air pollution. The PVA/CS electrospun membranes are becoming promising alternatives to substitute non-degradable polymers in surgical masks.

Although recycled poly(ethylene terephthalate) (rPET) is an attractive, sustainable feedstock for electrospinning, optimization of processing variables for filtration performance remains limited. This study quantifies how polymer concentration, flow rate, and applied voltage govern fiber morphology and key filtration metrics—collection efficiency (η), pressure drop (ΔP), quality factor (Q_f), and porosity—in rPET membranes. A fractional factorial design was employed to model interactions and identify trade-offs in filtration performance. The optimal condition was obtained at 16 wt.% PET, 1.2 mL·h⁻¹, and 22 kV, yielding uniform fibers with an average diameter of 328.6 nm and high filtration efficiencies (95.65–99.99%). The permeability constants were 1.07 × 10⁻¹² m² (20 wt.% PET) and 1.15 × 10⁻¹³ m² (8 wt.% PET), indicating an increase in permeability with increasing polymer concentration and fiber diameter. The 20 wt.% PET membrane delivered the highest Q_f of 0.0646 Pa⁻¹ with a low ΔP of 48.5 Pa at 4.8 cm·s⁻¹, reflecting a favorable balance between collection and airflow resistance. In summary, higher PET concentrations reduce flow resistance and improve Q_f, whereas lower concentrations yield finer fibers and high η at the expense of permeability. rPET nanofiber membranes, therefore, represent a sustainable and versatile route to high-efficiency, lower-pressure-drop air filters for residential, industrial, and commercial environments.

The recent SARS-CoV-2 pandemic brought to light the difficulty in controlling the pathogenic bioaerosols present in the air. So, several studies have sought efficient and mainly sustainable technologies to develop new filtering media and new biocidal and virucidal agents. Filter media composed of nanofibers stand out for having high collection efficiencies and high permeability. For this reason, they have been widely used in filters for indoor environments and in face masks. Combined with nanofibers or conventional filtering media, the addition of quaternary ammonium surfactants to provide biocidal action proves to be an ecologically sustainable alternative. Thus, the present work reviews these filtering mechanisms, their applications, and perspectives for novel uses of these technologies in engineering and materials science.

Background/Objectives: Chronic wounds remain difficult to manage because persistent inflammation, microbial colonization, and excess exudate require dressings that combine structural integrity, bioactivity, antimicrobial performance, and cytocompatibility. This study aimed to develop electrospun nanofibrous mats based on gelatin, poly(vinyl alcohol) (PVA), and poly(ε-caprolactone) (PCL), with and without Brazilian red propolis extract (BRPE), and to evaluate how extract incorporation affects solution properties, fiber morphology, fluid interaction, antimicrobial activity, and cytocompatibility. Methods: BRPE was characterized in terms of solid content, total phenolic content, antioxidant activity, and HPLC-DAD marker profile. Polymeric solutions were evaluated for electrical conductivity and rheological behavior and then processed by electrospinning under fixed conditions. The resulting mats were characterized by scanning electron microscopy, surface porosity, FTIR, and HPLC-DAD. Their performance was further assessed by swelling-associated degradation in simulated wound fluids, agar diffusion antimicrobial assays, and MTT cytocompatibility assays using HaCaT cells. Results: BRPE showed a solid content of 3.88%, a total phenolic content of 8.79 ± 0.21 mg pyrogallol equivalents g⁻¹ extract, and an antioxidant activity of 75.32 ± 9.80 mg Trolox equivalents g⁻¹ extract. HPLC-DAD confirmed preservation of the BRPE chromatographic fingerprint after electrospinning, with high retention of marker peaks associated with liquiritigenin and a formononetin-related signal. Solution conductivity varied with polymer composition and BRPE incorporation; for example, the PVA:gelatin:PCL formulation A4/A4.1 at 70:20:10 decreased from 919.6 to 539.6 µS cm⁻¹ after BRPE loading. Electrospinning produced continuous, defect-free fibers with mean diameters ranging from 94 to 224 nm and surface porosity between 9.8 and 10.6%. Most hydrophilic systems showed rapid fluid interaction but limited wet-state structural stability; among the quantified formulations, A5 showed the lowest mass loss, indicating better structural preservation under simulated wound conditions. BRPE-loaded mats showed microorganism-dependent antimicrobial activity, with the strongest inhibition against Staphylococcus epidermidis and Klebsiella pneumoniae and no activity against Pseudomonas aeruginosa. Free BRPE showed marked cytotoxicity, whereas selected electrospun formulations, especially A1.1 and A3.1, improved HaCaT cell viability. Conclusions: Electrospinning was an effective strategy for incorporating BRPE into polymeric nanofibers and modulating the physicochemical and biological performance of the resulting mats. These findings support the potential of these materials as multifunctional wound-dressing platforms, although further optimization is needed to improve wet-state structural stability, mechanical performance, and bioactive release.