Biomimetic calcium phosphates-based coatings deposited on binary Ti-Mo alloys modified by laser beam irradiation for biomaterial/clinical applications

Abstract

Biomimetic Method has been widely used to prepare calcium phosphate coatings on Ti and its alloys. This modification is based on a Synthetic/simulated Body Fluid (BSF) which facilitates the mimicking of the biological process in order to provide hard tissue repairs. The formation of HA and other calcium phosphates under biological medium and SBF occurs in the presence of Ca2+ and PO43- ions, as well as essential ions such as: Mg2+, HCO3-, K+ and Na+. Ti-15Mo alloy samples were irradiated by pulsed Yb: YAG pulsed laser beam under air and atmospheric pressure. Sequentially, calcium phosphate coatings were deposited on the irradiated surfaces by the biomimetic method. The biomimetic calcium phosphates-based surfaces were submitted to heat treatment conditions at 350°C and 600°C. The present study correlates two conditions of fluency (1,91 and 5,54 J.cm-2) as established have a sufficient energy to promote ablation on the laser beam irradiated surfaces. Likewise, it has been demonstrated the processes of fusion and fast solidification from the laser beam irradiation, under ambient atmosphere, inducing the formation of stoichiometric TiO2 and non-stoichiometric titanium oxides, including Ti3O5, TiO, Ti3O and Ti6O with different oxide percentages depending on the fluency applied. Besides that, laser modification has allowed a clean and reproducible process, providing no traces of contamination, an important feature for clinical applications. The physico-chemical and morphological analysis indicated the formation of a multiphase coatings depending on the heat treatment temperature performed to 350 °C (ACP1 and 2, HAD, HA phases) and 600 °C (HAD, HA and β-TCP phases). It is worth noting that multiphasic bioceramic systems has been gaining attention for biomedical applications. Thus, the laser beam irradiation associated to bioactive coatings of calcium phosphates of biological interest have shown to be promising and economically feasible for use in dental and orthopedic implants.