Greater osteoblast long-term functions on ionic plasma deposited nanostructured orthopedic implant coatings

Bioactive coatings are in high demand to increase the functions of cells for numerous medical devices. The objective of this in vitro study was to characterize for the first time osteoblast (bone-forming cell) long-term functions (such as proliferation and deposition of calcium containing mineral) on several potential orthopedic implant polymeric materials [specifically, ultrahigh molecular weight polyethylene (UHMWPE) and polytetrafluoroethylene (PTFE)] coated with nanostructured titanium using a novel ionic plasma deposition (IPD) coating process. UHMWPE is a widely used polymer in total knee and hip replacements, while PTFE is not, but it has been used in other orthopedic applications. The IPD coating process creates a surface-engineered nanostructure (with features usually below 100 nm) by first using a vacuum to remove all contaminants, and then guiding charged metallic ions or plasma to the surface of a medical device at ambient temperature. Results demonstrated that compared to currently used titanium and uncoated polymers, polymers coated with titanium using IPD significantly increased osteoblast proliferation and, most importantly, calcium deposition. In this manner, this study strongly suggests that IPD should be further studied for creating nanometer titanium surface feature coatings to enhance osteoblast functions necessary to increase orthopedic implant efficacy.