Nanocrystalline Diamond Coatings: Creation of Proper Surface Topography for Orthopedic Applications
- PDF / 360,302 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 27 Downloads / 214 Views
1138-FF12-16
Nanocrystalline Diamond Coatings: Creation of Proper Surface Topography for Orthopedic Applications 1 1,2 Lei Yang , Thomas J. Webster and Brian W. Sheldon 1 1 Division of Engineering, Brown University, Providence, RI 02912, USA 2 Department of Orthopedics, Brown University, Providence, RI 02912, USA ABSTRACT The idea of using nanocrystalline diamond (NCD) as a coating on orthopedic implants originates back to the last century since NCD possesses superior mechanical and tribological properties as well as chemical stability. However, it has only been within recent years that the interactions between NCD and osteoblasts (OB, bone forming cells) have been investigated. In this study, the impact of NCD surface topography on OB functions including proliferation (24 hrs to 48 hrs) and differentiation (7 to 21 days) was studied. NCD of varied grain sizes (from less than 100 nm to approximately 600 nm) were fabricated by microwave plasma enhanced chemical-vapor-deposition and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface topography of the NCD changed dramatically as grain size grew. OB proliferation on these coatings was studied by SEM after incubation for 24 hrs and 48hrs, respectively. OB differentiation on diamond coatings after incubation from 1 to 3 weeks was investigated by alkaline phosphatase activity and calcium deposition. Results demonstrated that OB proliferation and differentiation were dependent on topography with NCD grain sizes less than 100 nm exhibiting the best OB responses. To explain this enhancement, OB filopodia protrusions on different NCD were observed by SEM and the results revealed that surface topography of NCD played a crucial role in OB filopodia extensions. In summary, these findings provided important design criteria for creating proper NCD surfaces for orthopedic coatings and also provided cues on promoting interactions between nanostructured surfaces and cell responses.
INTRODUCTION In order to prolong the 10-15 year lifetime of current implants and reduce the need for revision surgeries, promoting bone cell functions at the bone-implant interface and fostering resistance to bio-chemical (erosion) and mechanical (especially wear) reactions are of great importance. Along these lines, it has been reported that diamond is one of the most robust materials for orthopedic applications to date, however, bone cell functions on diamond remain unclear. Recent researchers have revealed several promising approaches to improve bone cell interactions on implants by introducing nanoscale features [1]. This rationale has been also applied to diamond coatings on orthopedic implants. Specifically, nanocrystalline diamond (NCD) coatings have been investigated for their promise in orthopedic applications and recent studies have demonstrated their strong potential. For example, Amaral et al. [2] fabricated NCD on a Si3N4 substrate and demonstrated improved osteoblast (OB, bone forming cells) proliferation and synthesis of OB differentiation markers
Data Loading...
