Microbial adhesion and biofilm formation on bioactive surfaces of Ti-35Nb-7Zr-5Ta alloy created by anodization

Abstract

This study evaluated the microbial colonization (adhesion and biofilm) on modified surfaces of a titanium alloy, Ti-35Nb-7Zr-5Ta, anodized with Ca and P or F ions, with and without silver deposition. The chemical composition, surface topography, roughness (Ra), and surface free energy were evaluated before and after the surface modifications (anodizing). Adhesion and biofilm formation on saliva-coated discs by primary colonizing species (Streptococcus sanguinis, Streptococcus gordonii, Actinomyces naeslundii) and a periodontal pathogen (Porphyromonas gingivalis) were assessed. The surfaces of titanium alloys were modified after anodizing with volcano-shaped micropores with Ca and P or nanosized with F, both with further silver deposition. There was an increase in the Ra values after micropores formation; CaP surfaces became more hydrophilic than other surfaces, showing the highest polar component. For adhesion, no difference was detected for S. gordonii on all surfaces, and some differences were observed for the other three species. No differences were found for biofilm formation per species on all surfaces. However, S. gordonii biofilm counts on distinct surfaces were lower than S. sanguinis, A. naeslundii, and P. gingivalis on some surfaces. Therefore, anodized Ti-35Nb-7Zr-5Ta affected microbial adhesion and subsequent biofilm, but silver deposition did not hinder the colonization of these microorganisms.