Chitosan/PEO nanofibers electrospun on metallized track-etched membranes: fabrication and characterization

The development of next-generation adsorption, separation, and filtration materials is growing with an increased research focus on polymer composites. In this study, a novel blend of chitosan (CS) and polyethylene oxide (PEO) nanofiber mats was electrospun on titanium (Ti)-coated polyethylene terephthalate (PET) track-etched membranes (TMs) with after-treatment by glutaraldehyde in the vapor phase for enhancing the nanofiber stability by crosslinking. The prepared composite, titanium-coated track-etched nanofiber membrane (TTM-CPnf) was characterized by Fourier transform infra-red (FTIR), water contact angle, and scanning electron microscopy (SEM) analyses. Smooth and uniform CS nanofibers with an average fiber diameter of 156.55 nm were produced from a 70/30 CS/PEO blend solution prepared from 92 wt. % acetic acid and electrospun at 15 cm needle to collector distance with 0.5 mL/h flow rate and an applied voltage of 30 kV on the TTM-CPnf. Short (15 min) and long (72 h)-term solubility tests showed that after 3 h, crosslinked nanofibers were stable in acidic (pH = 3), basic (pH = 13), and neutral (pH = 7) solutions. The crosslinked TTM-CPnf material was biocompatible based on the low mortality of freshwater crustaceans Daphnia magna. The composite membranes comprised of electrospun nanofiber and TMs proved to be biocompatible and may thus be suitable for diverse applications such as dual adsorption–filtration systems in water treatment

Chitosan-collagen based film for controlled delivery of a combination of short life anesthetics

The present research was undertaken to develop a chitosan-collagen film for controlled delivery of combinations of local anesthetics. The film has been prepared by casting which is a versatile, rapid and low-cost approach distinguished by high reproducibility. The mechanical, morphological, and physicochemical properties of the films and the impact of the drug loading were evaluated. We showed that the formulations have a good combination of strength and flexibility with high water permeability. Surface morphology investigation indicates a variation in roughness depending on the loaded compound. Release studies were performed in controlled environments and the data processed by the Higuchi model to assess the dynamics of the release. The local anesthetics, lidocaine, tetracaine, and benzocaine, were uniformly distributed within the matrix and released in a rate and magnitude specific for the drug concentration and combination tunable in a range time from 6 h to 24 h. The films dissolve completely in the physiological environment within 24 h without leaving any toxic metabolites as both of the components are recognized as safe. In vitro cytotoxicity and cell proliferation tests performed on human dermal fibroblast demonstrate the biocompatibility and lack of cytotoxicity of the prepared formulations. © 2019 Elsevier B.V.Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [L01504]; Tomsk Polytechnic University [VIU-RSCABS-68/2019

Efficient Cu2+, Pb2+ and Ni2+ ion removal from wastewater using electrospun DTPA-modified chitosan/polyethylene oxide nanofibers

Diethylenetriaminepentaacetic acid-modified chitosan/polyethylene oxide nanofibers (CS-DTPA/PEO NFs) were developed for enhanced heavy metal ion adsorption. These nanofibers were prepared by electrospinning, and their morphology and structure were investigated by scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR), respectively. The ability of CS-DTPA/PEO NFs to removing copper (Cu2+), lead (Pb2+) and nickel (Ni2+) ions from aqueous solutions was tested at room temperature. The effects of [DTPA]/[NH2] molar ratio, pH and initial concentration of metal ions on their absorption capacity were investigated to optimize process conditions, using pseudo-first and apparent-second-order, Boyd and intraparticle diffusion models to determine the rate-limiting step of metal ions adsorption. In turn, Freundlich, Langmuir, Temkin and Dubinin-Radushkevich isotherm models were used to describe the experimental data. The results demonstrate a decrease in the ability of CS-DTPA/PEO NFs to adsorb metal ions in the following order: Cu2+>Pb2+>Ni2+. The adsorption equilibrium is established after 90 min from the first contact with solutions containing the metal ions, and data are described using the Langmuir isotherm model. The maximal adsorption capacities of CS-DTPA/PEO NFs for Cu2+, Pb2+ and Ni2+ions were 177, 142, 56 mg g−1, respectively. The stability and reproducibility of CS-DTPA/PEO NFs were determined after five adsorption–desorption tests. © 2020Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [NPU I LO1504, CZ.02.2.69/0.0/0.0/16_027/0008464]; Ministry of Science and Higher Education of the Russian Federation [WSWW2020-0011