Increased Osteoblast Adhesion on Nano-rough Anodized Titanium and CoCrMo

One approach to improve biological properties of current titanium and CoCrMo implant is to mimic the nanostructures of bone. Surface modification via anodization is popular to create such nanometer surface features on these metallic implants. The objective of the present study was to anodize titanium and CoCrMo and then determine osteoblast adhesion on such materials. Hydrofluoric acid was used as an electrolyte for anodization and different anodization conditions were applied for each metal. Osteoblast adhesion was determined by cell counting under a fluorescence microscope. The results demonstrated the ability to make nano-tube-like structures on anodized titanium compared to smooth surfaces before anodization. The inner diameters of the tubes were about 60 nm and the depths were limited to a few hundred nanometers. The original CoCrMo surface had micro-scale scratches and cracks probably due to mechanical processing but was mainly smooth at the nanoscale. On the contrary, the anodized CoCrMo possessed a very rough surface in the micro-scale as well as a porous structure within the nano-scale. For both titanium and CoCrMo, the results of osteoblast adhesion tests showed significantly (p<0.01) increased osteoblast numbers on anodized compared to unanodized metals; properties which make them useful for orthopedic applications.