Antimicrobial electrospun nanofiber mats of NaOH-hydrolyzed chitosan (HCS)/PVP/PVA incorporated with in-situ synthesized AgNPs: Fabrication, characterization, and antibacterial activity

Preparation and characterization of PVA/chitosan nanofibers loaded with Dragon's blood or poly helixan as wound dressings

Nanofibers have been investigated in regenerative medicine. Dragon's blood (DB)- and poly helixan PF (PHPF) are natural materials used in cosmetics. Herein, we generated DB- and PHPF-loaded polyvinyl alcohol/chitosan (PVA/CS/DB and PVA/CS/PHPF, respectively) nanofibers. PVA/CS/DB and PVA/CS/PHPF nanofibers had an average diameter of 547.5 ± 17.13 and 521 ± 24.67 nm, respectively as assessed by SEM, and a degradation rate of 43.1 and 47.6 % after 14 days, respectively. PVA/CS/DB and PVA/CS/PHPF nanofibers had a hemolysis rate of 0.10 and 0.39 %, respectively, and a water vapor transmission rate of ∼2200 g.m-2.day-1. These nanofibers exhibited favorable antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis in vitro. PVA/CS/DB and PVA/CS/PHPF nanofibers demonstrated a sustained release of 77.91 and 76.55 % over 72 h. PVA/CS/DB and PVA/CS/PHPF nanofibers had a high rate of cytocompatibility and significantly improved the viability of NIH/3T3 cells as compared with free drugs or unloaded nanofibers. Histological inspection via H&E and Verhoeff's staining demonstrated PVA/CS/DB and PVA/CS/PHPF nanofibers enhanced the wound healing and damaged tissue recovery of unsplinted wound models by promoting epithelial layer formation, collagen deposition, and enhancing the presence of fibroblasts. Conclusively, PVA/CS/DB and PVA/CS/PHPF can be introduced as potential wound dressing candidates with favorable properties.

Electrospinning and electrospun polysaccharide-based nanofiber membranes: A review

The electrospinning technology has set off a tide and given rise to the attention of a widespread range of research territories, benefiting from the enhancement of nanofibers which made a spurt of progress. Nanofibers, continuously produced via electrospinning technology, have greater specific surface area and higher porosity and play a non-substitutable key role in many fields. Combined with the degradability and compatibility of the natural structure characteristics of polysaccharides, electrospun polysaccharide nanofiber membranes gradually infiltrate into the life field to help filter air contamination particles and water pollutants, treat wounds, keep food fresh, monitor electronic equipment, etc., thus improving the life quality. Compared with the evaluation of polysaccharide-based nanofiber membranes in a specific field, this paper comprehensively summarized the existing electrospinning technology and focused on the latest research progress about the application of polysaccharide-based nanofiber in different fields, represented by starch, chitosan, and cellulose. Finally, the benefits and defects of electrospun are discussed in brief, and the prospects for broadening the application of polysaccharide nanofiber membranes are presented for the glorious expectation dedicated to the progress of the eras.

Environment-Friendly Preparation and Characterization of Multilayered Conductive PVP/Col/CS Composite Doped with Nanoparticles as Potential Nerve Guide Conduits

Tissue engineering constitutes the most promising method of severe peripheral nerve injuries treatment and is considered as an alternative to autografts. To provide appropriate conditions during recovery special biomaterials called nerve guide conduits are required. An ideal candidate for this purpose should not only be biocompatible and protect newly forming tissue but also promote the recovery process. In this article a novel, multilayered biomaterial based on polyvinylpyrrolidone, collagen and chitosan of gradient structure modified with conductive nanoparticles is presented. Products were obtained by the combination of electrospinning and electrospraying techniques. Nerve guide conduits were subjected to FT-IR analysis, morphology and elemental composition study using SEM/EDS as well as biodegradation. Furthermore, their effect on 1321N1 human cell line was investigated by long-term cell culture. Lack of cytotoxicity was confirmed by XTT assay and morphology study. Obtained results confirmed a high potential of newly developed biomaterials in the field of nerve tissue regeneration with a special focus on injured nerves recovery.

Electrospun Nanofiber-Based Bioinspired Artificial Skins for Healthcare Monitoring and Human-Machine Interaction

Artificial skin, also known as bioinspired electronic skin (e-skin), refers to intelligent wearable electronics that imitate the tactile sensory function of human skin and identify the detected changes in external information through different electrical signals. Flexible e-skin can achieve a wide range of functions such as accurate detection and identification of pressure, strain, and temperature, which has greatly extended their application potential in the field of healthcare monitoring and human-machine interaction (HMI). During recent years, the exploration and development of the design, construction, and performance of artificial skin has received extensive attention from researchers. With the advantages of high permeability, great ratio surface of area, and easy functional modification, electrospun nanofibers are suitable for the construction of electronic skin and further demonstrate broad application prospects in the fields of medical monitoring and HMI. Therefore, the critical review is provided to comprehensively summarize the recent advances in substrate materials, optimized fabrication techniques, response mechanisms, and related applications of the flexible electrospun nanofiber-based bio-inspired artificial skin. Finally, some current challenges and future prospects are outlined and discussed, and we hope that this review will help researchers to better understand the whole field and take it to the next level.

Preparation, Structure, and Properties of PVA-AgNPs Nanocomposites

The aim of the work was to prepare a polymer matrix composite doped by silver nanoparticles and analyze the influence of silver nanoparticles (AgNPs) on polymers' optical and toxic properties. Two different colloids of AgNPs were prepared by chemical reduction. The first colloid, a blue one, contains stable triangular nanoparticles (the mean size of the nanoparticles was ~75 nm). UV-vis spectrophotometry showed that the second colloid, a yellow colloid, was very unstable. Originally formed spherical particles (~11 nm in diameter) after 25 days changed into a mix of differently shaped nanoparticles (irregular, triangular, rod-like, spherical, decahedrons, etc.), and the dichroic effect was observed. Pre-prepared AgNPs were added into the PVA (poly(vinyl alcohol)) polymer matrix and PVA-AgNPs composites (poly(vinyl alcohol) doped by Ag nanoparticles) were prepared. PVA-AgNPs thin layers (by a spin-coating technique) and fibers (by electrospinning and dip-coating techniques) were prepared. TEM and SEM techniques were used to analyze the prepared composites. It was found that the addition of AgNPs caused a change in the optical and antibiofilm properties of the non-toxic and colorless polymer. The PVA-AgNPs composites not only showed a change in color but a dichroic effect was also observed on the thin layer, and a good antibiofilm effect was also observed.

Centrifugally Spun PVA/PVP Based B, N, F Doped Carbon Nanofiber Electrodes for Sodium Ion Batteries

Owing to their high electrical conductivity, high surface area, low density, high thermal stability, and chemical stability, carbon nanofibers have been used in many fields, including energy storage, electromagnetic shielding, filtering, composites, sensors, and tissue engineering. Considering the environmental impact of petroleum-based polymers, it is vital to fabricate carbon nanofibers from environmentally-friendly materials using fast and safe techniques. PVA/PVP nanofibers were fabricated via centrifugal spinning and the effects of variations in the PVP content on the morphology and thermal properties of PVA/PVP-blend nanofibers were studied using SEM and DSC analyses. Moreover, the effects of carbonization conditions, including stabilization time, stabilization temperature, carbonization time, and carbonization temperature on the morphology and carbon yield, were investigated. Centrifugally spun PVA/PVP-based carbon nanofiber electrodes with an average fiber diameter around 300 nm are reported here for the first time. Furthermore, centrifugally spun PVA/PVP-based B, N, F-doped carbon nanofibers were fabricated by combining centrifugal spinning and heat treatment. Through B, N, F doping, CNFs demonstrated a high reversible capacity of more than 150 mAh/g in 200 cycles with stable cycling performance.

Preparation of Needleless Electrospinning Polyvinyl Alcohol/Water-Soluble Chitosan Nanofibrous Membranes: Antibacterial Property and Filter Efficiency

Electrospinning is an efficient method of producing nanofibers out of polymers that shows a great potential for the filtration territory. Featuring water-soluble chitosan (WS-CS), a low-pollution process and a self-made needleless machine, PVA/WS-CS nanofibrous membranes were prepared and evaluated for nanofiber diameter, bacteriostatic property, filtration efficiency, pressure drop, and quality factor. Test results indicate that the minimal fiber diameter was 216.58 ± 58.15 nm. Regardless of the WS-CS concentration, all of the PVA/WS-CS nanofibrous membranes attained a high porosity and a high water vapor transmission rate (WVTR), with a pore size of 12.06–22.48 nm. Moreover, the membranes also exhibit bacteriostatic efficacy against Staphylococcus aureus, an optimal quality factor of 0.0825 Pa⁻¹, and a filtration efficiency as high as 97.0%, that is 72.5% higher than that of common masks.