Physicochemical Properties and Antibacterial Activity of Gellan Gum Incorporating Zinc Oxide/Carbon Nanotubes Bionanocomposite Film for Wound Healing.

Wound healing dressing based on a natural polymer of gellan gum incorporating zinc oxide nanoparticles and multiwall carbon nanotubes (GG/ZnONP + MWCNT) bionanocomposite film was fabricated via the solution casting method. The physicochemical properties of the film were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). Moreover, the antibacterial properties of the bionanocomposite film were investigated for wound healing applications. The characterization results confirmed the reinforcement of the gellan gum (GG) matrix with zinc oxide nanoparticles (ZnONP) and multiwall carbon nanotubes (MWCNT), as an amorphous GG/ZnONP + MWCNT bionanocomposite film was obtained. SEM morphological analysis shows that the addition of ZnONP and MWCNT nanofillers changed the film microstructure into a sponge-like structure that is more suitable for fluid uptake and thus more useful for wound healing. The GG/ZnONP + MWCNT bionanocomposite film demonstrated good antibacterial activity against all strains tested. Furthermore, macroscopic analysis shows that the wound treated with GG/ZnONP + MWCNT bionanocomposite film recovered completely (100%) in 14 days, compared to pure GG film (90.76%) and negative control (77.40%). As a result, the GG/ZnONP + MWCNT bionanocomposite film could be a promising wound dressing material.

In Situ Tungsten Carbide Formation in Nanostructured Copper Matrix Composite Using Mechanical Alloying and Sintering.

In this study, an in situ nanostructured copper tungsten carbide composite was synthesized by mechanical alloying (MA) and the powder metallurgy route. The microstructure and phase changes of the composite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Tungsten carbide phases (WC and W2C) were only present after MA and combination of sintering. Higher energy associated with a longer milling time was beneficial for the formation of WC. Formation of W2C and WC resulted from internal refinement due to heavy plastic deformation in the composite. The solubility of the phases in the as-milled and sintered composite was described by the changes of the lattice parameter of Cu. Chemical analysis of the surface of a composite of W 4f and C 1s revealed that the increased defects introduced by MA affect the atomic binding of the W-C interaction.

Photocatalytic and Antibacterial Properties of a 3D Flower-Like TiO2 Nanostructure Photocatalyst.

Flower-like titanium dioxide (TiO2) nanostructures are successfully synthesized using a hybrid sol-gel and a simple hydrothermal method. The sample was characterized using various techniques to study their physicochemical properties and was tested as a photocatalyst for methyl orange degradation and as an antibacterial material. Raman spectrum and X-ray diffraction (XRD) pattern show that the phase structure of the synthesized TiO2 is anatase with 80-100 nm in diameter and 150-200 nm in length of flower-like nanostructures as proved by field emission scanning electron microscope (FESEM). The energy-dispersive X-ray spectroscopy (EDS) analysis of flower-like anatase TiO2 nanostructure found that only titanium and oxygen elements are present in the sample. The anatase phase was confirmed further by a high-resolution transmission electron microscope (HRTEM) and selected area electron diffraction (SAED) pattern analysis. The Brunauer-Emmett-Teller (BET) result shows that the sample had a large surface area (108.24 m2/g) and large band gap energy (3.26 eV) due to their nanosize. X-ray photoelectron spectroscopy (XPS) analysis revealed the formation of Ti4+ and Ti3+ species which could prevent the recombination of the photogenerated electron, thus increased the electron transportation and photocatalytic activity of flower-like anatase TiO2 nanostructure to degrade the methyl orange (83.03%) in a short time (60 minutes). These properties also support the good performance of flower-like titanium dioxide (TiO2) nanostructure as an antibacterial material which is comparable with penicillin which is 13.00 ± 0.02 mm inhibition zone against Staphylococcus aureus.

Characterization data of titanate compounds synthesized using hydrothermal method at various temperature.

Titanate compounds was synthesized using hydrothermal method at various temperature (100, 150, 200, and 250 °C) for 24 hours. As-synthesized titanate was characterized using FTIR, XRD and nitrogen gas adsorption. FTIR spectra was scanned from 4000 to 400 cm-1 using Perkin Elmer Spectrum 100 FTIR spectrophotometer. XRD diffractogram was performed by using Rigaku Miniflex (II) X-ray diffractometer operating at a scanning rate of 2.00° min-1. The diffraction spectra were recorded at the diffraction angle, 2θ from 10° to 80° at room temperature. Nitrogen gas adsorption analysis was studied by using Micromeritics ASAP2020 (Alaska) to determine the surface area and pores size distribution. The nitrogen adsorption and desorption was measured at 77 K (temperature of liquid nitrogen) and the samples were degassed in a vacuum at 110 °C under nitrogen flow for overnight prior to analysis.

Physicochemical Properties of a Highly Efficient Cu-Ion-Doped TiO2 Nanotube Photocatalyst for the Degradation of Methyl Orange Under Sunlight.

In this study, a series of copper-ion-doped titanium dioxide (Cu-ion-doped TiO2) nanotubes (NTs) were synthesized via a hydrothermal method by the concentration variation of doped Cu ions (0.00, 0.50, 1.00, 2.50, and 5.00 mmol). In addition, the samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), nitrogen gas adsorption measurements, and ultraviolet-visible (UV-Vis) diffuse-reflectance spectroscopy. The photocatalytic activity of the Cu-iondoped TiO2 NTs was investigated for the degradation of methyl orange (MO) under sunlight. The results obtained from the structural and morphological studies revealed that, at low concentrations of Cu-doped TiO2 NTs, Cu is incorporated into the interstitial positions of the TiO2 lattice, affording a new phase of TiO2 (hexagonal) instead of the anatase TiO2 (tetragonal) observed for undoped TiO2 NTs. EDX analysis confirmed the presence of Cu in the TiO2-based photocatalyst. All of the investigated samples exhibited a hollow fibrous-like structure, indicative of an NT morphology. The inner and outer diameters of the NTs were 4 nm and 10 nm, respectively. The photocatalysts exhibited a large surface area due to the NT morphology and a type IV isotherm and H3 hysteresis, corresponding to the mesopores and slit-shaped pores. The Cu-ion-doped TiO2 NTs were excited by sunlight because of their low bandgap energy; and after the incorporation of Cu ions into the interstitial positions of the TiO2 lattice, the NTs exhibited high visible-light activity owing to the low bandgap.