Event Abstract Back to Event Inverse behavior between osteoblasts and fibroblasts on carbon-coated titanium surfaces Chie Yoshihara1, Takeshi Ueno1, Peng Chen2, Yusuke Tsutsumi2, Takao Hanawa2 and Noriyuki Wakabayashi1 1 Tokyo Medical and Dental University, Removable Partial Prosthodontics, Japan 2 Tokyo Medical and Dental University, Metallic Biomaterials, Japan Introduction: Biocompatibility, which is a critical factor in bone-implant integration, depends on surface physicochemical properties. For example, hydrocarbon deposition on titanium surface is inevitable, which can be a critical factor on cellular activity. Previous research demonstrated that osteoblastic activity including proliferation and differentiation was downregulated by carbon deposition dependently [1]. Surface analysis of failed oral implants revealed that significant amount of carbon was detected from most cases of implant surfaces [2]. Reported bone-implant contact percentage is 46 ± 16 %, indicating that implant surface is surrounded by fibrous tissue except for bone tissue [3]. Therefore, it would be important to investigate the cellular compatibility with carbon deposition for fibroblasts on titanium surfaces. This study examined the initial bioactivity of osteoblasts and fibroblasts on carbon-coated titanium surfaces. Materials and Methods: The film thickness of carbon was adjusted using a carbon coater so that it would be 5,25,50 nm on the Ti disk. The elemental component on the Ti surface was analyzed by X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the Ti surface was measured by means of an automated contact angle measuring devise. MC3T3-E1 cells and NIH3T3 cells were cultured for 4h and 24h on Ti disks with or without carbon depositon. The cell attachment activity was evaluated by WST-8-based colorimetry, and by calcein staining. Cell spreading behavior was evaluated by cell morphology analysis. Results: The XPS spectra showed that the C1s peak was increased with the increase of carbon thickness, and the Ti2p and O1s peak was decreased. Wettability was decreased depending on the carbon deposition. After 4h of culture, the number of attached MC3T3-E1 cells on 50nm of carbon-coated surfaces was 20% lower than that on 5nm surfaces(fig.1), and it was 37% decrease for 24h culture on 50 nm surfaces from 5 nm surfaces. For NIH3T3 cells, the number of attached cells on 50nm surfaces was increased by 60% compared to that on 5nm surfaces at 4h of culture(fig.2). The increase of the number of attached cells on 50 nm surfaces was maintained even after 24h, which was 40% higher than that on 5 nm surfaces. NIH3T3 cells showed expanded cell size with higher carbon coating, whereas MC3T3-E1 cell spreading were suppressed depending on carbon deposition. Discussion and Conclusion: The initial behavior of osteoblast and fibroblast was influenced by the levels of carbon deposition on titanium surface. Interestingly, it was an inverse relationship. This finding suggests that to control carbon deposition on titanium surfaces would be a key factor for bone-implant relationship. Furthermore, it would be indicated that hydrocarbon decomposition before the placement of titanium implants could help achieve the better bone-implant integration. Fig. 1.2. Cell attachment of osteoblast and fibroblast evaluated by WST-8 after 4h of culture. Data are mean osteoblast and fibroblastρ<.05, indicating a statistically significant difference among four different carbon-coated titanium surfaces.