Carbon nanohorn coating by electrodeposition accelerate bone formation on titanium implant.

Direct contact between bone and implant materials is required for dental implants. Titanium is used for the implant material owing to its mechanical and biological properties. The anodisation as the surface treatment was employed to enhance osteogenesis around titanium. Moreover, carbon nanohorn (CNH), a type of nanometer-sized carbon material, was reported to promote the bone formation. Thus, it is expected that if the surface of anodised Ti (AnTi) is modified with CNHs, Ti-bone contact would be enhanced. In this study, the Ti surface was modified with CNHs by electrophoresis and obtained anodised titanium coated with CNHs (CNH/AnTi). In vitro, CNH/AnTi attracted osteoblastic cells more than AnTi, thereby the proliferation of osteoblastic cell was enhanced by CNH/AnTi more than by AnTi. In vivo, at 7 and 28 days after implantation of CNH/AnTi or AnTi into the rat femur, more aggressive bone formation was observed on the surface of CNH/AnTi than on AnTi. More importantly, the area where newly formed bone tissue directly attached to CNH/AnTi was significantly larger than that for AnTi, suggesting that "contact osteogenesis" was accelerated on CNH/AnTi during the early post-implantation period. CNH/AnTi would be advantageous especially for the early stages of bone regeneration after surgery.

3D printed solution flow type microdroplet cell for simultaneous area selective anodizing.

INTRODUCTION: Recent advancements in 3D printing technology allow us to design and fabricate customized droplets cells for localized electrochemical patterning. OBJECTIVES: In this study, 3D printed solution-flow type microdroplet cell (Sf-MDC) is proposed for localized anodizing of two different regions on Al surface. The effect of printing orientation on 3D printing parameters is elucidated to minimize the resin consumption, printing time and material wastage. The capability of Sf-MDC to fabricate porous alumina patterns with adjustable pore size and thickness is explored by varying the length of Pt wire inside each capillary. METHODS: The Sf-MDC was optimally fabricated using 3D printer at the highest possible resolution. The Al specimens were electropolished in 13.6 kmolm-3 CH3COOH/2.56 kmolm-3 HClO4 at 278 K and 28 V for 145 s. 0.22 kmolm-3 oxalic acid (COOH)2 solution was prepared for anodizing. The specimen was set on pulse-XYZ stage controller and anodized (at 50 V and 323 K) using the Sf-MDC. RESULTS: Anodizing with Sf-MDC resulted in the formation of two uniformly sized porous alumina lines on the specimen. Porous alumina lines exhibited similar pore geometry, interpore distance and pores arrangement, suggesting uniform supply of current to both the droplets. Layered-type cross-sectional structure with each layer having a thickness of 2.7 mm was formed for both the porous alumina lines. By varying the length of Pt wire inside each capillary, porous alumina lines with different porous structure and oxide thickness were simultaneously fabricated. CONCLUSIONS: Simultaneous anodizing with Sf-MDC can be applied for fast fabrication of porous alumina filters with different porous structure and for various patterning applications.

Aluminum microstructures on anodic alumina for aluminum wiring boards.

The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices.

Synthesis of aluminum oxy-hydroxide nanofibers from porous anodic alumina.

A novel method for the synthesis of aluminum oxy-hydroxide nanofibers from a porous anodic oxide film of aluminum is demonstrated. In the present method, the porous anodic alumina not only acts as a template, but also serves as the starting material for the synthesis. The porous anodic alumina film is hydrothermally treated for pore-sealing, which forms aluminum oxy-hydroxide inside the pores of the oxide film as well as on the surface of the film. The hydrothermally sealed porous oxide film is immersed in the sodium citrate solution, which selectively etches the porous aluminum oxide from the film, leaving the oxy-hydroxide intact. The method is simple and gives highly uniform aluminum oxy-hydroxide nanofibers. Moreover, the diameter of the nanofibers can be controlled by controlling the pore size of the porous anodic alumina film, which depends on the anodizing conditions. Nanofibers with diameters of about 38-85 nm, having uniform shape and size, were successfully synthesized using the present method.