Titanium (Ti) is one of the most used biomaterials in metals. However, Ti is typically artificial materials. Thus, it is
necessary for improving the biocompatibility of Ti. Recently, coating of the titanium dioxides (TiO2) film on Ti plate has
been proposed to improve biocompatibility of Ti. We have developed coating method of the film on Ti plate with an
aerosol beam. Periodic structures formation on biomaterials was also a useful method for improving the biocompatibility.
Direction of cell spreading might be controlled along the grooves of periodic microstructures. In our previous study,
periodic nanostructures were formed on the film by femtosecond laser irradiation at fundamental wave (775 nm). Period
of the periodic nanostructures was about 230 nm. In cell test, cell spreading along the grooves of the periodic
nanostructures was observed although it was not done for the film without the periodic nanostructures. Then, influence
of the period of the periodic nanostructures on cell spreading has not been investigated yet. The period might be changed
by changing the laser wavelength. In this study, the periodic nanostructures were created on the film with femtosecond
laser at 775nm and 388 nm, respectively. After cell test, cell spreading along the grooves of the periodic nanostructures
was observed on 775 nm and 388nm laser irradiated areas. Distribution of direction of cell spreading on laser irradiated
area was also examined. These results suggested that controlling the cell spreading on periodic nanostructures with
period of 230 nm was better than that with period of 130 nm.
Titanium dioxide (TiO2) has a variety of functions, but cannot be activated by visible-light illumination. It is importance to extend the activity of TiO2 into the visible-light, which comprises the larger portion of the room light. Therefore, the visible-light activated TiO2 is required. We developed it with the femtosecond laser irradiation. The TiO2 films irradiated with femtosecond laser were darkened without changing topography of the TiO2 film surface. In the visible-light photocataltic function measurements, the TiO2 films were evaluated with the acetaldehyde decomposition test. The concentration of acetaldehyde was decreased to over time. This result indicated that visible-light activated photocatalyst function of TiO2 films were generated by femtosecond laser irradiation.
Periodic nanostructures formation on Titanium dioxide (TiO2) film by scanning of femtosecond laser beam spot at fundamental and second harmonic wave is reported. Titanium (Ti) is one of the most widely used for biomaterials, because of its excellent anti-corrosion and high mechanical properties. However, Ti implant is typically artificial materials and has no biofunction. Hence, it is necessary for improving the bioactivity of Ti. Recently, coating of TiO2 film on Ti plate surface is useful methods to improve biocompatibility of Ti plate. Then, if periodic nanostructures were formed on the film surface, cell spreading might be controlled at one direction. We propose periodic nanostructures formation on TiO2 film by femtosecond laser irradiation. Cell spread could be controlled along the grooves of periodic nanostructures. In the experiments, the film was formed on Ti plate with an aerosol beam. A commercial femtosecond Ti : sapphire laser system was employed in our experiments. Periodic nanostructures, lying perpendicular to the laser electric field polarization vector, were formed on the film at fundamental and second harmonic wave. Periodic nanostructures were also produced on Ti plate with femtosecond laser. The period of periodic nanostructures on the film was much shorter than that on Ti plate. By cell test, there was a region of cell spreading along the grooves of periodic nanostructures on the film formed with femtosecond laser at fundamental wave. On bare film surface, cell spreading was observed at all direction. These results suggest that direction of cell spread could be controlled by periodic nanostructures formation on the film.