THE INTERACTION OF FIBROBLASTS WITH DIAMOND-LIKE-CARBON COATED TITANIUM

Abstract

Introduction: Due to uneven distribution of stress between the stump and the socket in amputees pain, infection and necrosis of soft tissue can be problematic (Dudek, Marks, & Marshall 2006)Implants have been developed that allow the external prostheses to attach directly to the skeleton by a percutaneous section by osseointegration that reduces the stresses on the soft tissue alleviating the problems associated with a socket (Lai et al. 1998). It has been postulated that surface coatings can enhance soft tissue attachment and increase the in growth of fibroblastic dermal tissues enhancing the seal at the skin implant interface and reducing infection (Pendegrass et al. 2006). Hydrogenated (acetylene: C2H2) and silanized (tetra methyl silane: TMS) diamond-like-carbon coating (DLC) can be applied to titanium(Ti) alloy to reduce surface energy and hydrophilicity. It was hypothesized that biomaterial surfaces having high surface energy and high hydrophilicity eg, Ti alloy enhance the adhesion and maturation of human dermal fibroblasts when compared with C2H2 and TMS coated substrates in vitro.

Methods: Fibroblasts were cultured on 10 mm diameter Ti alloy, C2H2 and TMS coated Ti alloy discs for 4 hours and 24 hours (2500 cells per disc). Cell area and attachment were analysed using Image Analysis and quantification of immunolocalised vinculin containing adhesion plaques respectively. The number of plaques per cell and cell area were compared between experimental groups and controls at 4 and 24 hours. The change in cell area and number of adhesion plaques between 4 and 24 hours were compared for each substrate type. SPSS version 10 was used for the statistical analysis.

Results: At 4 and 24 hours, the number of adhesion plaques was significantly greater on control and C2H2 compared with TMS (p< 0.001). No significant difference was observed between control and C2H2 discs (p> 0.05). At 4 hours, cell area was significantly greater in control compared to both C2H2 and TMS (p< 0.001). At 4 hours, the cell area in TMS was significantly greater than C2H2 (p< .001). At 24 hours, the cell area on control and C2H2 was significantly greater than TMS(p< 0.001). However, there was no significant difference between cell area on control and C2H2 (p> 0.05). From 4 to 24 hours, the number of adhesion plaques increased significantly on all the surfaces (p< 0.001). Cell area increased significantly on C2H2 and TMS between 4 and 24 hours. No significant increase in the cell area was observed on control substrates

Discussion: This supports the hypothesis that surfaces with high surface energy and high hydrophilicity lead to increased cell attachment and cell area. Thus, it can be concluded that the hydrophilic surfaces with higher surface energies favour the adhesion of dermal fibroblasts.