Comparative characteristics of antimicrobial properties of titanium dioxide coating in the anatase form on the surface of titanium and its alloys

Products from titanium and its alloys are actively used for the reconstruction of the musculoskeletal and maxillofacial systems of the body. However, in some cases, their rejection is observed, which is associated with the addition of bacterial infections. To accelerate the process of osseointegration, various methods of surface treatment are used, including sandblasting, which creates a certain microrelief, as well as the deposition of a bioactive coating of titanium dioxide (TiO2) with the anatase structure. Since the method of TiO2 formation, namely atomic layer deposition (ALD), has a certain sensitivity to the structure and chemistry of the initial surface, especially in the low-thickness range, the characteristics of the coating may depend on the implant material. Therefore, the purpose of this study is to evaluate the antiadhesive and antimicrobial properties of titanium and its alloy samples, taking into account the differences in their structure and type of surface treatment, including the formation of a TiO2 coating with anatase crystalline structure. Materials and methods. In order to quantitatively evaluate the in vitro microbial adhesion to samples of Grade 4 titanium (ASTM F67) and Ti6Al4V (ASTM F136)/Ti6Al7Nb (ASTM F1295) alloys with different surface treatments, authors used microbiological, molecular biological methods and statistical analysis. Results. The work studies samples of titanium and its alloys with various surface preparation, that can be used for orthopedic treatment. Comparative assessment was carried out for the first time which included adhesion of sanitary-significant microorganisms (for example, S. aureus, E. coli) and anaerobic bacteria to the studied samples. The lowest level of adhesion was observed on Ti6Al4V samples coated with TiO2, which indicates their bactericidal and fungicidal properties. Samples containing niobium (Ti6Al7Nb) showed selective anti-adhesive properties, which confirms their activity against viable microbial cells. Conclusions. The results highlight the potential effectiveness of TiO2 coating with anatase crystalline structure for utilization in medical implants and structures.