Masaya Shimabukuro

Titanium (Ti) and its alloys are commonly used in medical devices. However, biomaterial-associated infections such as peri-implantitis and prosthetic joint infections are devastating and threatening complications for patients, dentists, and orthopedists and are easily developed on titanium surfaces. Therefore, this review focuses on the formation of biofilms on implant surfaces, which is the main cause of infections, and one-step micro-arc oxidation (MAO) as a coating technology that can be expe

Recently, the problem of infection on implanted devices caused by the formation of biofilms has been recognized. Surface treatment to prevent the initial stages of bacterial adhesion and subsequent bacterial growth is the only possible solution against such infection. In this study, simple electrochemical treatment was used for introducing silver, an antibiotic agent, on the titanium surface. A porous oxide layer containing small amounts of silver was formed on the metal of the substrate. This w

This study investigated the efficacy of copper (Cu) as an antibacterial element incorporated on titanium (Ti) surface by electrochemical treatment. Cu was incorporated onto Ti surface by micro-arc oxidation (MAO). A small amount of Cu was incorporated into the oxide layer and was found to be in oxidized states. Cu-incorporated samples exhibited no-harmful effect on the proliferation of osteoblastlike cells. Moreover, the difference in antibacterial property between fresh and incubated samples wa

The effects of Ti, Nb, Ta, Zr, and Ag on cellular and bacterial adhesion were investigated in this study. Moreover, the relationships between surface compositions, metal ion release behaviors, and biological responses were examined. As a result, MC3T3-E1 cells and S. aureus were able to better attach to Ti and Zr rather than the Nb and Ta specimens. For the Ag specimen, the amount of Ag ions released into Hanks’ solution was the largest among all the specimens. Cellular and bacterial adhesion on

This study investigated the time transient effect of zinc (Zn) in the porous titanium dioxide formed by micro-arc oxidation (MAO) treatment routinely performed for Zn-containing electrolytes. The aim of our analysis was to understand the changes in both the chemical and biological properties of Zn in physiological saline. The morphology of the Zn-incorporated MAO surface did not change, and a small amount of Zn ions were released at early stages of incubation in saline. We observed a decrease in

Recently, silver (Ag) and copper (Cu) have been incorporated into a titanium (Ti) surface to realize their antibacterial property. This study investigated both the durability of the antibacterial effect and the surface change of the Ag- and Cu-incorporated porous titanium dioxide (TiO₂) layer. Ag- and Cu-incorporated TiO₂ layers were formed by micro-arc oxidation (MAO) treatment using the electrolyte with Ag and Cu ions. Ag- and Cu-incorporated specimens were incubated in s

Fracture-related infections require both treatments for bacteria removal and bone reconstruction. The use of combined broad-spectrum antibacterial silver compounds and artificial bone with high osteogenic activity is considered to be an effective strategy for achieving these treatments in one surgery. However, silver compounds are toxic for living tissues even at low concentrations. Herein, we investigated the no-observed-effect level (NOEL) of silver phosphate (Ag₃PO₄) in

A customized micro arc oxidation (MAO) treatment technique was developed to obtain desirable antibacterial properties on titanium surfaces. The two-step MAO treatment was applied to fabricate a specimen containing both Ag and Zn in its surface oxide layer. Surface analyses and metal-ion release tests were performed to evaluate the presence of Ag and Zn and the ion release behavior for simulating practical usage, respectively. Additionally, the antibacterial properties of the specimens were also

Ti surfaces must exhibit antibacterial activity without cytotoxicity to promote bone reconstruction and prevent infection simultaneously. In this study, we employed a two-step electrochemical treatment process, namely, microarc oxidation (MAO) and cathodic electrochemical deposition (CED), to modify Ti surfaces. During the MAO step, a porous TiO₂ (pTiO₂) layer with a surface roughness of approximately 2.0 μm was generated on the Ti surface, and in the CED step, Cu was depos

This study investigates the interaction between E. coli bacteria and various surface states of Cu. Pure Cu was oxidized at 298 K, 673 K, and 1273 K, and its surface chemical state was characterized using X-ray photoelectron spectroscopy. The oxidized specimens were immersed in both bacteria-free and bacteria-containing solutions, and the release of Cu ions from each specimen was evaluated. As a result, the specimens, which existed as mainly Cu0 or Cu+ on the surface, exhibited the same corrosion

The composition of carbonate apatite (CO₃ Ap) aids bone regeneration. Other features, such as porosity and pore interconnectivity of artificial bone, also govern bone regeneration. In general, a trade-off exists between the porosity and mechanical strength of artificial bone. Therefore, this suggests that the interconnected pores in the ant-nest-type porous (ANP) structure of artificial bone accelerate bone regeneration by minimizing the sacrifice of mechanical strength. The unique st

In their application in medical devices, zirconium (Zr) and its alloys are expected to prevent the generation of magnetic resonance imaging artifacts owing to their magnetic susceptibilities. The one-step micro-arc oxidation (MAO) process in electrolytes of phosphate, calcium, and silver (Ag) ions may endow the Zr surface with osteogenic cell compatibility and antibacterial activity, owing to the formation of porous oxide layers consisting of the electrolyte and substrate elements. Herein, we fo

Implant-associated infections are threatening and devastating complications that lead to bone destruction and loss. As a smooth surface is suitable for inhibiting bacterial adhesion, endowing antibacterial activity to the Ti surface without any structural changes in the surface topography is an effective strategy for preventing infection. The thin film on the Ti-6Al-4 V surface was functionalized to endow antibacterial activity by immersion in a Cu(OH)₂ solution. The resulting surface