The bioactive and anti-bacterial Cu-based bioceramic TiO2 coatings have been fabricated on cp-Ti (Grade 2) by two-steps. These two-steps combine micro-arc oxidation (MAO) and physical vapor deposition–thermal evaporation (PVD-TE) techniques for dental implant applications. As a first step, all surfaces of cp-Ti substrate were coated by MAO technique in an alkaline electrolyte, consisting of Na3PO4 and KOH in de-ionized water. Then, as a second step, a copper (Cu) nano-layer with 5 nm thickness was deposited on the MAO by PVD-TE technique. Phase structure, morphology, elemental amounts, thickness, roughness and wettability of the MAO and Cu-based MAO coating surfaces were characterized by XRD (powder- and TF-XRD), SEM, EDS, eddy current device, surface profilometer and contact angle goniometer, respectively. The powder- and TF-XRD spectral analyses showed that Ti, TiO2, anatase-TiO2 and rutile-TiO2 existed on the MAO and Cu-based MAO coatings’ surfaces. All coatings’ surfaces were porous and rough, owing to the presence of micro sparks through MAO. Furthermore, the surface morphology of Cu-based MAO was not changed. Also, the Cu-based MAO coating has more hydrophilic properties than the MAO coating. In vitro bioactivity and in vitro antibacterial properties of the coatings have been investigated by immersion in simulated body fluid (SBF) at 36.5 °C for 28 days and bacterial adhesion for gram-positive (S. aureus) and gram-negative (E. coli) bacteria, respectively. The apatite layer was formed on the MAO and Cu-based MAO surfaces at post-immersion in SBF and therefore, the bioactivity of Cu-based MAO surface was increased to the MAO surface. Also, for S. aureus and E. coli, the antibacterial properties of Cu-based MAO coatings were significantly improved compared to one of the uncoated MAO surfaces. These results suggested that Cu-based MAO coatings on cp-Ti could be a promising candidate for biomedical dental implant applications.

/pdf/characterization-bioactivity-and-antibacterial-properties-of-1z15mk8ren.pdf

Characterization, Bioactivity and Antibacterial Properties of Copper-Based TiO2 Bioceramic Coatings Fabricated on Titanium

Depending on the requirements of specific applications, implanted materials including metals, ceramics, and polymers have been used in various disciplines of medicine. Titanium and its alloys as implant materials play a critical role in the orthopedic and dental procedures. However, they still require the utilization of surface modification technologies to not only achieve the robust osteointegration but also to increase the antibacterial properties, which can avoid the implant-related infections. This article aims to provide a summary of the latest advances in surface modification techniques, of titanium and its alloys, specifically in biomedical applications. These surface techniques include plasma spray, physical vapor deposition, sol-gel, micro-arc oxidation, etc. Moreover, the microstructure evolution is comprehensively discussed, which is followed by enhanced mechanical properties, osseointegration, antibacterial properties, and clinical outcomes. Future researches should focus on the combination of multiple methods or improving the structure and composition of the composite coating to further enhance the coating performance.

/pdf/surface-modification-techniques-of-titanium-and-its-alloys-klwoc8xja1.pdf

Surface Modification Techniques of Titanium and its Alloys to Functionally Optimize Their Biomedical Properties: Thematic Review.

The plasma electrolytic oxidation is an innovative method for the surface treatment of titanium and its alloys. This review provides an overview of the historical development of the process and summarizes the current state of the art. The chemical as well as the electro- and plasma-chemical basics of the layer forming mechanisms, which comprises the substrate/electrolyte interface before discharge initiation and the different types and stages of plasma electrolytic discharge phenomena are explained within the context of titanium-based materials. How these phenomena can be influenced by the use of suitable electrolytes and controlled by the electrical regime is described. Subsequently, the microstructures and composition of the layers are described in detail, and the properties for specific applications are then discussed. The resistance of a PEO coating to corrosive environments, tribological factors, and alternating mechanical stress is viewed critically, and the extensive functional properties such as physiological compatibility, photocatalytic activity, and decorative properties are revealed. Finally, examples of various practical applications in the medical engineering, aviation, automotive, and environmental technology fields, as well as other branches of industry, are presented.

Review of plasma electrolytic oxidation of titanium substrates: Mechanism, properties, applications and limitations

Formation and in vitro/in vivo performance of "cortex-like" micro/nano-structured TiO 2 coatings on titanium by micro-arc oxidation

In this study, as a first step, a silver (Ag) thin film layer was deposited on cp-Ti (Grade-2) by thermal evaporation-physical vapor deposition (TE-PVD). And then, Ag-based titanium surface was coated by micro-arc oxidation (MAO) in solution, consisting of sodium silicate and potassium hydroxide at the second step. The phase structure, surface morphology, elemental composition, functional groups, wettability and surface topography of both coatings were characterized by XRD, SEM, EDS-mapping, contact angle goniometer, ATR-FTIR and surface profilometer, respectively. The XRD results indicated that anatase and rutile were detected on the surface after MAO and TE + MAO. Both coatings' surfaces were rough and porous due to the existence of plasma chemical reactions on micro discharge channels. The Ag-incorporated MAO coating exhibited much more hydrophilic character than MAO coating. The Ag was homogeneously distributed through the surface. The biological properties such as bioactivity and anti-bacterial tests of the coatings were analyzed by immersion test in SBF and bacterial formation. The apatite-forming abilities of both coatings were evaluated by soaking in simulated body fluid (SBF) up to 28 days. After soaking, apatite structure was formed on the MAO and Ag-incorporated MAO surfaces and the bioactivity of MAO surface on Ti was considerably improved compared to the MAO surface under SBF conditions. The homogenous and dense apatite distribution was observed on Ag-incorporated MAO coatings. The bacterial adhesion of Ag-incorporated MAO coatings was significantly reduced compared to plain MAO surface.

Huiying Liu

Papers

Formation and in vitro/in vivo performance of "cortex-like" micro/nano-structured TiO 2 coatings on titanium by micro-arc oxidation

Formation and characterization of titania coatings with cortex-like slots formed on Ti by micro-arc oxidation treatment