Fabrication and Characterization of Biological Electrospinning Nanofiber Scaffold Based on Cellulose Diacetate-Gelatin-Green Tea for Tissue Engineering Applications
Tissue engineering has developed novel therapies such as many types of wound dressings, bio-pads, scaffolds and bandages, in order to reduce the effects of deep and extensive skin wounds. Here, we have produced an electrospun nanofiber scaffold, based on biodegradable materials such as gelatin (as a natural and hydrophilic polymer) and cellulose diacetate (with optimal biodegradability), in order to increase wound healing using nanotechnology. We also used green tea extract for its anti-oxidant and anti-bacterial effect, to improve the biological properties of the scaffold. In the fabrication process, two polymer solutions: 1. Gelatin (with acetic acid solvent) and 2. Cellulose Diacetate (with acetone solvent) mixed with green tea extract, were prepared. Then they were spun using a two-nozzle electrospinner to produce a hybrid nanofiber scaffold. SEM images showed enough finesse and uniformity of the produced scaffold to simulate the extracellular matrix. Further, measuring the contact angle of water droplet and the web surface, indicated optimal hydrophilicity of the nanofiber scaffold, which controls the level of scaffold degradability and cell adhesion. Also, the results of antibacterial tests for two bacterial strains (E. coli and S. aureus) showed the antibacterial characteristics of the extract-containing scaffold. In addition to previous tests, evaluation of fibroblast morphology on the nanofiber scaffolds, indicated appropriate cell adhesion and expansion, that confirms the biocompatibility of this produced scaffold.
Dependence of Alloy Composition in Color Change of Brass Foil by Oxide Thin Layer Formation
It is known that copper foil undergoes a color change in heating by oxide thin layer formation. Therefore, we focused on the color change by the oxidation of brass foil. Brass foil (Akaguchi (Cu87%Zn13% alloy) and Aoguchi (Cu85%Zn15% alloy)) also undergoes color change by oxidation, and it shows heating time and temperature dependence. Brass foil need longer heating time to appear color change than copper foil, and we can visually confirm that the brass has corrosion resistant. In addition, color change of brass foil depends on the percentage of copper in the brass, and Aoguchi shows rapidly color change in same heating condition. We show that brass has different physical properties than copper, even with a high percentage of copper in brass, and this was verified through comparison using diffusion length and RGB data in Aoguchi and Akaguchi. We demonstrate these colored brass foils are used as art materials, and our results expanded material using possibility of brass foil.