RESUMEN
Low-density green polyethylene (LDGPE) composites reinforced with 5 wt% of bamboo fiber and 3 wt% of a compatibilizing agent (polyethylene grafted with maleic anhydride and tannin) were processed through extrusion and injection molding. Bamboo fiber, Bambusa Vulgaris, was characterized using Fourier-transform infrared spectroscopy (FTIR). The molded specimens were analyzed for their thermal, mechanical, and morphological properties. The estimated concentration was chosen to provide the best mechanical strength to the material studied. FTIR analysis of the fibers revealed the presence of groups characteristic of bamboo fiber and tannin. Differential scanning calorimetry revealed that both compatibilizing agents increased the matrix's degree of crystallinity. However, scanning electron microscopy (SEM) showed that, despite the presence of compatibilizing agents, there was no significant improvement in adhesion between the bamboo fibers and LDGPE.
RESUMEN
Abstract This study developed and characterized a method for controlled deposition of thin films of hydroxyapatite on titanium surfaces. Thirty-three titanium cylinders were randomly divided: negative control/polished (A), acid etched (B) and coated by hydroxyapatite (C). Acid etch was performed in an aqueous solution of nitric acid. The cylinders were subjected to coating by a thin film of hydroxyapatite with dip-coating method. These cylinders were submitted to a pre-heat treatment 450°C/10 minutes and 800°C/2 hours. Scanning electron microscopy analysis demonstrated a homogeneous and smooth surface (A), an irregular and porous surface (B) and a crystalline deposition (C). The X-ray energy dispersive analysis showed characteristic elements of hydroxyapatite (C). Analysis by X-ray diffraction showed the presence of characteristic peaks of hydroxyapatite, corresponding to the structural composition of hydroxyapatite. Cell viability (MTT-assay in NIH-3T3-Cells) test demonstrated no differences between the groups. Titanium surfaces coated with a hydroxyapatite film by the dip-coating method suggest adequate control of deposition of thin films of hydroxyapatite and similar cell viability using mouse fibroblasts.
RESUMEN
Alginate hydrogel (AH) has intrinsic physical and biological limitations that hinder its broader application in tissue engineering. We hypothesized that the inclusion of nanofibers in the hydrogel and the use of a biotemplate that mimics nature would enhance the translational potential of alginate hydrogels. In this study, we have shown a method to obtain nano-/microfibers of titanium (nfTD) and hydroxyapatite (nfHY) using cotton as a biotemplate. These fibers were incorporated in the alginate hydrogel and the mechanical characteristics and biological response to these reinforced materials were evaluated. We observed that these nanofibers resembled the structure of natural collagen and did not mediate cell toxicity. The incorporation of nfTD or nfHY to the AH has not increased the viscosity of the hydrogel. Therefore, this is a feasible method to produce a scaffold with improved physical characteristics, while at the same time generating an enhanced environment for cell adhesion and proliferation.