Improved cytocompatibility of nanosecond-pulsed laser-treated commercially pure Ti surfaces

In this study, we developed a surface modification technology for implants using commercially pure (cp) Ti. The technology used in this study leads to reduction in the time required for adhesion between bone and surfaces of implants. The existence ofmicroasperities and oxide layers is important to induce calcium phosphate precipitation and bone formation activity of osteoblasts. In addition, we focused on nanosecondpulsed laser treatment as a method to create both microasperities and oxide layers. First, we observed surface morphologies formed by laser treatment. An oxide layer with high oxygen concentration and microasperities on the order of 10 nm to 10 μmwere produced. Moreover, the OH groups were created on the laser-treated surface. Second, by culturing osteoblasts on the laser-treated cp Ti surface, its effects on cell shape, proliferation, and activity of bone formation were evaluated. Even though cell proliferation was at a comparable level in these two surfaces, the ALP activity per cell number was improved by about four times in the laser-treated surface compared with that in the polished surface. On the laser-treated cp Ti surface, it was considered that the bone formation activity of osteoblasts was promoted without inhibiting cell proliferation. From the results of this study, it is possible to conclude that by treating cp Ti surfaces with a laser, a surface with good cytocompatibility can be created.