Biological behavior of fibroblast-like cells cultured on anodized-hydrothermally treated titanium with a nanotopographic surface structure

PURPOSE: The interface between the transmucosal portion of endosseous implants surface and the connective tissue is characterized by fibroblast-rich barrier tissue, which is important for the long-term stability and maintenance of the implant. This study investigated the effect of cell adhesion on focal adhesion kinase (FAK) protein and on gene expression over a 72-h culture period. Fibroblast-like cells were cultured on anodized-hydrothermally treated commercially pure titanium with nanotopographic structure (SA-treated c.p.Ti) surfaces. METHODS: Murine fibroblast-like NIH/3T3 cells were cultured for 10-72h on c.p.Ti, anodic oxide (AO) c.p.Ti, and SA-treated c.p.Ti disks. Cell morphology was analyzed using scanning electron microscopy (SEM). Cytoskeletal structure and FAK protein localization were analyzed using confocal laser scanning microscopy (CLSM). FAK mRNA levels were analyzed using real-time quantitative RT-PCR. RESULTS: SEM and CLSM showed increased NIH/3T3 cell adhesion with time, and actin filaments oriented parallel with the filopodium-like extensions on all disks. Filopodium-like extensions were bound tightly to the nanotopographic structure surface of cultures on SA-treated c.p.Ti, and especially at 72h. FAK protein was localized along cellular extensions on SA-treated c.p.Ti and the expression of FAK mRNA was significantly higher on these disks than on c.p.Ti and AO c.p.Ti after 72h (P<0.05). CONCLUSIONS: NIH/3T3 fibroblast-like cells have the capacity to adhere to SA-treated c.p.Ti as a transmucosal portion of implant surface material and express focal adhesion molecules, which may play a key role in the maintenance of a mucosal tissue barrier.