Chitosan Membrane Containing Copaiba Oil (Copaifera spp.) for Skin Wound Treatment

The interaction of copaiba oil in the polymer matrix of chitosan can produce a favorable synergistic effect and potentiate properties. Indeed, the bioactive principles present in copaiba oil have anti-inflammatory and healing action. In the present work, chitosan membranes containing different contents of copaiba oil copaíba (0.1, 0.5, 1.0 and 5.0% (v/v)) were for the first time investigated. The membranes were developed by the casting method and analyzed for their morphology, degree of intumescence, moisture content, contact angle, Scanning Electron Microscope, and X-ray diffractometry. These chitosan/copaiba oil porous membranes disclosed fluid absorption capacity, hydrophilic surface, and moisture. In addition, the results showed that chitosan membranes with the addition of 1.0% (v/v) of copaiba oil presented oil drops with larger diameters, around 123.78 μm. The highest fluid absorption indexes were observed in chitosan membranes containing 0.1 and 0.5% (v/v) of copaiba oil. In addition, the copaiba oil modified the crystalline structure of chitosan. Such characteristics are expected to favor wound treatment. However, biological studies are necessary for the safe use of chitosan/copaiba oil membrane as a biomaterial.

Synthesis and Characterization of 2-Decenoic Acid Modified Chitosan for Infection Prevention and Tissue Engineering

Chitosan nanofiber membranes are recognized as functional antimicrobial materials, as they can effectively provide a barrier that guides tissue growth and supports healing. Methods to stabilize nanofibers in aqueous solutions include acylation with fatty acids. Modification with fatty acids that also have antimicrobial and biofilm-resistant properties may be particularly beneficial in tissue regeneration applications. This study investigated the ability to customize the fatty acid attachment by acyl chlorides to include antimicrobial 2-decenoic acid. Synthesis of 2decenoyl chloride was followed by acylation of electrospun chitosan membranes in pyridine. Physicochemical properties were characterized through scanning electron microscopy, FTIR, contact angle, and thermogravimetric analysis. The ability of membranes to resist biofilm formation by S. aureus and P. aeruginosa was evaluated by direct inoculation. Cytocompatibility was evaluated by adding membranes to cultures of NIH3T3 fibroblast cells. Acylation with chlorides stabilized nanofibers in aqueous media without significant swelling of fibers and increased hydrophobicity of the membranes. Acyl-modified membranes reduced both S. aureus and P. aeruginosa bacterial biofilm formation on membrane while also supporting fibroblast growth. Acylated chitosan membranes may be useful as wound dressings, guided regeneration scaffolds, local drug delivery, or filtration.

Effect of Weak Magnetic Field on the Structure and Physical Properties of Chitosan Membranes

The purpose of this study was to evaluate the effect of weak magnetic fields on the structure and physical properties of chitosan (Ch) membranes. The membranes were prepared by a casting method using chitosan and a solvent of acetic acid. The magnetic field of 1.5 mT is applied during the membrane-forming reaction with administration times of 2, 4, 8, and 12 hours. The membranes formed were named M-2h, M-4h, M-8h, and M-12h, respectively. The chitosan membrane without magnetic fields is used as a control, namely M-0. The structure and physical properties of the membranes were examined using Fourier Transform Infra-Red (FTIR) spectrophotometer, water uptake test, dynamic mechanical analysis (DMA), and X-ray diffraction (XRD). The result showed that the membranes with magnetic fields are thicker compared to the control membrane. FTIR analysis revealed that some peaks of the membranes with magnetic fields shifted to the higher or lower wavenumber with increased or decreased absorption intensity. The membranes become stronger and more flexible; their degree of crystallinity increases as increasing the time of the magnetic fields' application, and their hydrophilicity improved. The membranes' crystal structure becomes more regular, and their degree of crystallinity increases as increasing the time of the application of the magnetic fields; and their mechanical properties such as ultimate tensile strength, tensile modulus, and elongation at break were improved. Those results explain that the structure and physical properties of chitosan membranes were significantly affected by the membrane-forming reaction's magnetic fields.

Activity Test, Selectivity, Stability of Chitinase on Amobil Chitosan Membranes

The use of enzymes for industrial functions needs enzymes that are stable, selective and might be used repeatedly. The aim of the study was to determine the chitinase enzyme's function, selectivity, and stability in amobil chitosan membranes. The research method consisted of stages: production of the chitinase enzyme which included the manufacture of chitin colloidal substrate, rejuvenation of thermophilic bacteria, preparation of the inoculum and determining the optimum time of production, fractionation of ammonium sulfate, chitinase enzyme immobilization technique and activity, stability and selectivity test of amobil enzyme. The results demonstrated that chitinase activity, which incorporates the optimum temperature and thus the optimum concentration of production within the immobilization technique, had an optimum temperature of 65oC on day 4 of production time with an OD value of 0.9876. The selectivity of amobil chitinase with metal ions Cd (II), Pb (II), Zn (II), and Hg (II) demonstrated that amobil chitinase was selective for these ions. Eamobil chitinase was heat stable at 55-75oC and resistant to organic solvents, suggesting that it could be used repeatedly.