The effect of green tea extract as a natural and ecofriendly antibacterial additive on the healing effect of chitosan/ polyethylene oxide wound dressing nanofiber was investigated. Three different polymeric nanofiber composite including chitosan, chitosan/polyethylene oxide and chitosan/polyethylene oxide/green tea extract, was produced by electrospinning method and was used as wound dressing. Affecting parameters on electrospinning method such as voltage, feed rate, nozzlecollector distance and content of green tea in nanofiber structure were studied and optimized. The morphology of electrospun nanofibers was studied with use of scanning electron microscope. The average diameters of prepared nanofibers was determined by Image J software. The optimum conditions for preparation of electrospun nanofibers were: Voltage; 20 kV, feed rate; 0.5 ml/h, nozzle-collector distance; 10 cm, and chitosan/polyethylene oxide weight ratio; 0.9. Stability, water absorption and degradation of prepared nanofibers were investigated by placing the prepared nanofibers for 24 hours in a solution of acetate buffer with a pH of 5.5 and a temperature of 37 o C. Moreover, the antibacterial activity of composite scaffolds were tested by Agar plate method by two type bacteria including Escherichia coli and Staphylococcus aureus. Furthermore, the healing ability of the prepared nanofibers was studied on the rat's wound. Chitosan/polyethylene oxide/ green tea showed the best healing effects in comparison with the other prepared wound dressings. These results confirmed that green tea extract helps to keep wound surface moist, reduces inflammation and increases the speed of recovery and healing.

In this work BaFe 2 O 4 nanostructure have been produced hydrothermal method using PTSA (p-toluenesulfonic acid) as fuel. The as-produced nanostructures were characterized by techniques like X-ray powder diffraction (XRD), Fourier transform infrared spectra (FT-IR), Energy-dispersive X-ray spectrometry (EDS), Scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The photocatalytic oxidation of dibenzothiophene (DBT), benzothiophene (BT) and dodecanethiol (RSH) in model oil was studied at room temperature (30 o C) with catalyst. The system contained BaFe 2 O 4 , H 2 O 2 , and acetonitrile liquid, UV-Vis lamp which played vitally important roles in the photocatalytic oxidative desulfurization. Especially, the molar ratio of H 2 O 2 and sulfur (O/S) was only 3:1, which corresponded to the stoichiometric reaction. The sulfur removal of DBT-containing model oil with BaFe 2 O 4 could reach 96.6%. The system could be recycled seven times without a significant decrease in photocatalytic activity.

In this work, nanofibers of chitosan/poly (ethylene oxide) (PEO) with an average fiber diameter from a few microns down to about 30 nm and a narrow size distribution were fabricated by a fast electrospinning process using a handheld electrospinning device. It was found that the matrix with a formulation of chitosan/PEO ratio of 90/10 (w/w) and 0.3% Triton V R X-100 retained excellent integrity of the fibrous structure in 0.5M acetic acid solution. The characterization of nanofibrous structure by scanning electron microscope (SEM) imaging showed the homogeneity of nanofibrous structure without consid-erable bead-like structures. The excellent electrospinnability of the current formulation represents electrospinning of natural biopolymer chitosan as a useful process in various biomedical applications, especially as potential wound dressing agents. Nonwoven mats and polymer solutions with composition chitosan/PEO ratio of 90/10 and 60/40 showed excellent antibacterial activity against E. coli and P. aeruginosa. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 000: 000-000, 2011

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