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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. [Display omitted] [ABSTRACT FROM AUTHOR]

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. [Display omitted] [ABSTRACT FROM AUTHOR]

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, 1H 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. [Display omitted] Chitosan nanofibers encapsulating copper oxide nanoparticles by needleless electrospinning High antioxidant and antimicrobial activity Tunable air permeability, vapor water transmission rate and dedusting ability High mechanical properties and soil biodegradability [ABSTRACT FROM AUTHOR]

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. [Display omitted] [ABSTRACT FROM AUTHOR]

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. [Display omitted] • Chitosan/TMC nanofibers were prepared by electrospinning using PEO as sacrificial additive. • They had strong antimicrobial activity, while being in vitro and in vivo biocompatible. • In wet media, they presented high swelling, fluid exchange and biodegradability. • They had good muco- and bio-adhesiveness and mechanical properties similar to skin. • Applied on burn wounds in rats, they favored rapid healing and fully tissue restoration. [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]