Abstract.Pulse current electrodeposition is a technique of special interest, due to the advantages it has, like easy operation, high control in the amount, homogeneity and purity of the deposited material, and low cost. This work studies the influence of the pulsed electrodeposition parameters variation on the characteristics of calcium phosphates coatings, including the composition, crystallinity and morphology. The influence of the current density and pulse on and off time on the physicochemical properties of the obtained coatings were evaluated. The coatings were electrodeposited on Ti6Al4V using Ca(NO3)2·H2O and NH4H2PO4 with a Ca/P molar ratio of 1.67. The coatings were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The analysis of DRX confirmed the formation of HAP. The results revealed that the variation of the current density modified the morphology of the coating. Also, the amount of material deposited increases as the off-time pulse increases, allowing the diffusion of the ions in the solution towards the working electrode.
Se evaluó la interacción de un biomaterial polimérico con medio de cultivo y células osteoblásticas, electrodepositado sobre Ti6Al4V. El compuesto está integrado por ácido poliláctico-ácido poliglicólicohidroxiapatita, modificado con quitosano y colágeno. Se calculó la permitividad relativa con los datos de impedancia plasmada en un espectro dieléctrico que permitió identificar las dispersiones alfa y beta, relacionadas con el intercambio iónico y la polarización de la membrana celular. La adhesión y proliferación celular se analizaron mediante microscopia de epifluorescencia, en donde fue posible observar al tercer día del cultivo celular el proceso de mitosis representado por la condensación del núcleo y la separación de los cromosomas. Se observó la morfología de la superficie del biomaterial mediante SEM (Scanning Electron Microscope) y AFM (Atomic Force Microscope) y se evaluó la actividad celular mediante la medición de fosfatasa alcalina. Finalmente se encontró la mejor superficie para la adhesión y crecimiento celular mediante análisis estadístico, que correspondió al recubrimiento con la mayor concentración de quitosano y colágeno.
Composite materials of polymer – carbon nanotubes have been widely studied for biomedical applications due to the versatility of polymers in this field and the excellent mechanical, thermal and electrical properties of carbon nanotubes. However, carbon nanotubes are materials which can provide some toxicity in biological systems, since they have low solubility in water and organic solvents, tend to form aggregates in solution, are bioincompatible and limited compatibility with polymeric matrices. For this reason, carbon nanotubes considered for biomedical applications must comply with this basic requirement of solubility. To improve the compatibility of the carbon nanotubes, they were exposed to treatment with HNO3, NaOH and HCl to eliminate impurities and improve the solubility in other solvents. Polycaprolactone coatings at 2.5% w/v and multi-wall carbon nanotubes (0.5, 1.0 and 1.5 g/L) were developed to evaluate the electrochemical and bioactive properties. Techniques such as infrared spectroscopy, contact angle, scanning electron microscopy, atomic force microscopy, electrochemical impedance spectroscopy using simulated body fluid as electrolyte and the bioactivity of human osteoseosarcoma cells (HOS ATCC® CRL-1543) by alkaline phosphatase were used. From the reported characterizations, it was observed that the resistance to polarization increases according to the degree of dispersion of carbon nanotubes present in the polymer matrix, decreasing the degradation rate of the material.
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