Incorporação de óleo essencial de Melaleuca alternifolia em solução de policaprolactona para recobrimento de titânio comercialmente puro aplicado como biomaterial

Abstract

Advances in health and bioengineering have enabled the development of medical devices that allow partial or total recovery of organs and tissues damaged due to accidents or degenerative diseases. Metallic prostheses are the most used, with titanium being the most applied metal in their manufacture, due to its mechanical properties combined with excellent biocompatibility. In order to enhance the device to be implanted, the application of polymeric and ceramic biomaterials is being studied. The use of polycaprolactone has shown promising characteristics, due to its biodegradability. In orthopedic substitutes, the addition of hydroxyapatite has favored the osteointegration process. However, complications related to infectious processes are recurrent to surgical procedures. As a strategy to minimize post-surgical bacterial contamination, the present project proposed the incorporation of essential oil of Melaleuca alternifolia as a natural bactericide, covering polycaprolactone and hydroxyapatite on a titanium substrate (grade 4). The samples were characterized by Scanning Electron Microscopy, Dispersive Energy Spectroscopy, X-Ray Diffraction and Fourier Transform Infrared Spectroscopy, demonstrating that the coating was performed over the entire surface of the material and that the incorporation of essential oil did not alter the morphology of the polymeric film. Aiming to evaluate the biological performance and the evolution of the growth of the apatitic superficial layer, the samples were submitted to a bioactivity test in a Simulated Body Fluid medium for four weeks. It was found also an evolution of the hydroxyapatite layer in a homogeneous way and with a globular characteristic, appreciable for the osteointegrative process. The curves obtained in the corrosion test showed that the coating combining hydroxyapatite, polycaprolactone and the essential oil was more resistant to the corrosive process, as it presents a higher corrosion potential. To evaluate the antimicrobial activity of the essential oil, the samples were subjected to microbiological assays of disk-diffusion on agar for the strains of Staphylococcus aureus and Escherichia coli. The inhibition halos formed were small in size, with Escherichia coli cultures being more sensitive to essential oil. Therefore, it is concluded that the proposed systems have desirable characteristics for application in medical implants, suggesting that they are favorable to the osteointegrative process.