Controlled surface modification of Ti6Al4V using biomimetic mineralization via thermo-chemical route improves bioactivity

Ti alloy (Ti6Al4V) sheets were bio-activated by a two-step thermo-chemical treatment followed by biomimetic mineralization. The samples were then characterized by standard techniques and evaluated of their mechanical properties, electrochemical corrosion potential and biological performance. The intermediate layer corresponding to thermo-chemical treatment displayed anatase TiO₂ peaks and the final bio-mineralization resulted in a globular hydroxyapatite (HAP) layer. Thermo-chemical treatment yielded a two-fold increase (98.79% increment) in microhardness value, whereas, the biomimetically activated samples showed a very small decrease in the same owing to their ceramic behavior. The surface hydrophobicity of the bio-activated surface was found reduced significantly, might assist to facilitate improved cell adhesion. Electrochemical corrosion measurements exhibited an increase in corrosion potential and decrease in current density of the samples, suggested increased corrosion resistant. The surface coating on the Ti6Al4V sheet also demonstrated enhanced cytocompatibility as no toxic effect of the samples could be perceived to human keratinocyte cell line (HaCaT). Similarly, the samples showed higher hemocompatibility and enhanced bactericidal activity. Our study concluded that the surface coating of Ti6Al4V sheets significantly improved corrosion resistance and bioactivity of the substrates, which can be applied for various biomedical applications.