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This paper focuses on the preparation of chitosan-based nanofibers embedding copper oxide nanoparticles to create multifunctional materials that meet the demands of contemporary applications. To this end, a mixture of chitosan, quaternized chitosan and poly (ethylene glycol) was used as polymeric matrix, considering their own contribution to the final material's properties and their ability to stabilize the copper oxide nanoparticles. An exhaustive investigation of the nanofibers was done in order to assess their composition and morphology (FTIR, 1 H NMR, WXRD, TGA, SEM, TEM, POM, UV-vis) and to study their mechanical, antimicrobial and antioxidant properties, air and water permeability and ability for air filtration. It was shown that the copper oxide nanoparticles were anchored into the polymeric matrix via strong hydrogen bonding and electrostatic interactions, which induced the improvement of the mechanical properties and antioxidant activity. The copper oxide nanoparticles favored the thinning of the fibers during electrospinning process and improved the antibacterial activity and dust filtration capacity. Besides, the fibers displayed air permeability and vapor water transmission rate similar to synthetic nanofibers, while being biodegradable. All these performances recommend the new materials for developing antibacterial eco-materials with good breathability to be used as hygienic textiles, masks, or air filters., Competing Interests: Declaration of competing interest The authors declare no financial interests, directly or indirectly related to the work submitted for publication., (Copyright © 2024. Published by Elsevier B.V.)

The paper reports new chitosan-based nanofibers, designed to address the healing of burn wounds. To this aim, mesoporous chitosan fiber mats were prepared by electrospinning using poly(ethylene oxide) as sacrificial additive, followed by loading with norfloxacin and coating with an antifungal agent via dynamic imine bonds. Dynamic vapor sorption experiment proved intra-fiber mesopores around 2.7 nm, and UV-vis, FTIR, and NMR spectroscopy confirmed the norfloxacin embedding and the imination reaction. SEM, AFM and POM techniques displayed semicrystalline nanofibers with average diameter around 170 nm entangled into a non-woven mat. Their mesoporous nature favored a rapid adsorption of fluids up to 17 g/g, and a biodegradation rate fitting the wound healing rate, i.e. up to 30 % mass loss in media of pH characteristic to wound exudate and total degradation in that characteristic to normal dermis. The composite fibers released the NFX and 2FPBA in a controlled manner, and showed antimicrobial activity against gram positive, gram negative and fungal strains. They had no cytotoxic effect on normal human dermal fibroblasts, and showed biocompatibility on experimental rats. The investigation of wound healing ability on second/third-degree burn model in rats revealed wound closure and total restoration of the fully functional dermis and epidermis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The paper aimed to prepare quaternary chitosan-based nanofibers as bioabsorbable wound dressings. To this aim, fully biodegradable chitosan/N,N,N-trimethyl chitosan (TMC) nanofibers were designed and prepared via electrospinning, using poly(ethylene glycol) as sacrificial additive. The new biomaterials were structurally and morphologically characterized by FTIR and NMR spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy, and their properties required for wound dressings application were investigated and discussed in detail. Thus, the nanofiber behavior was investigated by swelling, dynamic vapor sorption, and in vitro biodegradation in media mimicking the wound exudate. The mechanical properties were analysed from the stress-strain curves, the bioadhesivity from the texture analysis and the mucoadhesivity from the Zeta potential and transmittance measurements. The antimicrobial activity was assessed against S. aureus and E. coli strains, and the biocompatibility was tested in vitro on normal human dermal fibroblasts, and in vivo on rats. The application of the fiber mats with the best balance of properties as dressings on deep burn wound models in rats showed wound closure and active healing, with fully restoration of epithelia. It was concluded that the combination of chitosan with TMC into nanofibers provides new potential bioabsorbable wound dressing, opening new perspectives in regenerative medicine., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The industrial production of chitosan, initiated over 50 years ago, has transformed its application across diverse industries, agriculture, and medicine. To enhance its properties, numerous chitosan derivatives have been synthesized. The quaternization of chitosan has proven beneficial, as it not only enhances its properties but also imparts water solubility, expanding its potential for a wider range of applications. Specifically, the utilization of quaternized chitosan-based nanofibers has leveraged the synergistic benefits of quaternized chitosan (including hydrophilicity, bioadhesiveness, antimicrobial, antioxidant, hemostatic, and antiviral activities, as well as ionic conductivity) in combination with the distinctive characteristics of nanofibers (such as a high aspect ratio and 3D architecture). This combination has permitted numerous possibilities, spanning from wound dressings, air and water filters, drug delivery scaffolds, antimicrobial textiles, to energy storage systems and alkaline fuel cells. In this comprehensive review, we examine the preparation methods, properties, and applications of various composite fibers containing quaternized chitosan. The advantages and disadvantages of each method and composition are meticulously summarized, while relevant diagrams and figures illustrate the key findings., Competing Interests: Declaration of competing interest The authors declare no financial interests, directly or indirectly related to the work submitted for publication., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Chitosan based nanofibers are emerging biomaterials with a plethora of applications, especially in medicine and healthcare. Herein, binary quaternized chitosan/chitosan fibers are reported for the first time. Their preparation strategy consisted in the electrospinning of ternary chitosan/quaternized chitosan/poly(ethylene oxide) solutions followed by the selective removal of poly(ethylene oxide). Their morphology and performances were systematically investigated and discussed in detail. It was found that the fibers had reversible water vapor adsorption/desorption and showed swelling degrees similar to commercial wound dressings. They presented good mechanical properties and the content of quaternized chitosan modulated their bioadhesion, mucoadhesion and biodegradation rate and conferred them strong antimicrobial activity. Tests on normal human fibroblasts confirmed their safely use in contact with tissues and the biocompatibility investigation on rats showed no harmful effect when subcutaneous implanted. All these proved the binary quaternized chitosan/chitosan fibers as bioactive materials suitable for tissue regeneration, wound healing and drug delivery systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Chitosan is a biopolymer originating from renewable resources, with great properties which make it an attractive candidate for plenty of applications of contemporary interest. By manufacturing chitosan into nanofibers using the electrospinning method, its potential is amplified due to the enhancement of the active surface and the low preparation cost. Many attempts were made with the aim of preparing chitosan-based nanofibers with controlled morphology targeting their use for tissue engineering, wound healing, food packaging, drug delivery, air and water purification filters. This was a challenging task, which resulted in a high amount of data, sometimes with apparent contradictory results. In this light, the goal of the paper is to present the main routes reported in the literature for chitosan electrospinning, stressing the advantages and disadvantages of each of them. Special emphasis is placed on the influence of various electrospinning parameters on the morphological characteristics of the fibers and their suitability for distinct applications. [ABSTRACT FROM AUTHOR]

A series of seven low molecular weight compounds containing triazole, pyridine-N-oxide, and one substituted aromatic ring linked together by heteroatoms containing spacers was synthesized by click chemistry reaction. The compounds were structurally characterized by FTIR, NMR, as well as single-crystal X-ray diffraction. Their morphologic, thermotropic, and photophysical properties were determined by dynamic light scattering, scanning electron microscopy, atomic force microscopy, polarized light microscopy, UV-vis, and photoluminescence spectroscopy. The triazole derivatives proved to have porous 3D supramolecular architectures determined by an extensive nonclassical hydrogen bonding network. They spontaneously crystallized into long nanofibers and exhibited typical molecular glass behavior, aggregation induced emission as well as crystallization induced emission enhancement. [ABSTRACT FROM AUTHOR]

Herein, the effect of three deterpenated fractions from Origanum majorana L. essential oil on the physicochemical, mechanical and biological properties of chitosan/β-chitin nanofibers-based nanocomposite films were investigated. In general, the incorporation of Origanum majorana L. original essential oil or its deterpenated fractions increases the opacity of the nanocomposite films and gives them a yellowish color. The water solubility decreases from 58% for chitosan/β-chitin nanofibers nanocomposite film to around 32% for the nanocomposite films modified with original essential oil or its deterpenated fractions. Regarding the thermal stability, no major changes were observed, and the mechanical properties decreased. Interestingly, data show differences on the biological properties of the materials depending on the incorporated deterpenated fraction of Origanum majorana L. essential oil. The nanocomposite films prepared with the deterpenated fractions with a high concentration of oxygenated terpene derivatives show the best antifungal activity against Aspergillus niger, with fungal growth inhibition of around 85.90%. Nonetheless, the only nanocomposite film that does not present cytotoxicity on the viability of L929 fibroblast cells after 48 and 72 h is the one prepared with the fraction presenting the higher terpenic hydrocarbon content (87.92%). These results suggest that the composition of the deterpenated fraction plays an important role in determining the biological properties of the nanocomposite films. [ABSTRACT FROM AUTHOR]

Chitosan nanofibrous membranes are prepared via an electrospinning technique and explored as potential wound healing patches. In particular, the effect of a physical or chemical crosslinking treatment on the mat morphological, mechanical, water-related, and biological properties is deeply evaluated. The use of phosphate ions (i.e., physical crosslinking) allows us to obtain smooth and highly homogenous nanofibers with an average size of 190 nm, whereas the use of ethylene glycol diglycidyl ether (i.e., chemical crosslinking) leads to rougher, partially coalesced, and bigger nanofibers with an average dimension of 270 nm. Additionally, the physically crosslinked mats show enhanced mechanical performances, as well as greater water vapour permeability and hydrophilicity, with respect to the chemically crosslinked ones. Above all, cell adhesion and cytotoxicity experiments demonstrate that the use of phosphate ions as crosslinkers significantly improves the capability of chitosan mats to promote cell viability owing to their higher biocompatibility. Moreover, tuneable drug delivery properties are achieved for the physically crosslinked mats by a simple post-processing impregnation methodology, thereby indicating the possibility to enrich the prepared membranes with unique features. The results prove that the proposed approach may lead to the preparation of cheap, biocompatible, and efficient chitosan-based nanofibers for biomedical and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

The paper reports the preparation and characterization of a series of functionalized chitosan nanofibers designed for tissue engineering. Their functionalization was done by imination with two aldehydes with complementary bioactivity, one possessing antimicrobial activity and the other one having potential to enhance it by improving the cell permeability. The degree of imination of the fibers and the dynamic character of the imine units were investigated by FTIR, 1H NMR and UV–vis spectroscopy, while their morphology was assessed by scanning electron microscopy and polarized light microscopy. The swelling ability and biodegradation were determined in conditions mimicking the physiological environment, i.e. saline buffer and lysozyme medium at 37 °C. Preliminary biocompatibility and antimicrobial properties were evaluated by MTS assay on normal human dermal fibroblasts, and by disk diffusion method against relevant bacterial and fungal reference strains. The fibers showed fast swelling, biodegradation in the presence of lysozyme, biocompatibility and antimicrobial activity. It was concluded that the imination of chitosan nanofibers with two different aldehydes is a promising route towards biomaterials with improved properties for tissue engineering. [Display omitted] • Double functionalized chitosan nanofibers were prepared by imination with two aldehydes. • They showed aldehyde release due to the dynamic character of the imine bonds. • The double imination was a useful tool to control the swelling and biodegradation rate. • The new biomaterials are biocompatible and have antimicrobial properties. [ABSTRACT FROM AUTHOR]