SEM of electrochemically applied coating of hydroxyapatite on metal implant.

SEM of electrochemically applied coating of hydroxyapatite on metal implant.

Speaking of hydroxyapatite, there apparently is a new process for coating metal implants that could improve the outcomes of total joint replacement surgeries. Researchers at Tel Aviv University say their new electrochemical method improves upon current implant choices by enhancing an implants’ functionality, longevity and integration.

Hydroxyapatite is a great coating – one that nicely mimics the inorganic contents of bone and other body materials, and provides an important barrier between the metallic components of an implant and blood or other fluids.

The first method typically thought of for applying coatings would probably be plasma-spraying. Noam Eliaz, a professor at the university’s School of Mechanical Engineering, instead tried putting an prospective implant into a bath of electrolyte solution and applying an electric current.

He says his coating is actually better than one applied with a plasma-spraying technique. His studies show that the electrolytic method resulted in a 33% decrease in the level of materials failure (i.e., delamination) in the implants he coated.

Eliaz presented his findings to the 215th meeting of the Electrochemical Society in San Francisco in May 2009. In addition, a new 12-week implantation study, recently published in the journal Acta Biomaterialia, favorably compared the performance of the Tel Aviv University coatings to those of current commercial coatings.

Next up, Eliaz is going to focus on integrating nanoparticles and pharmaceuticals into the coating. “We can incorporate biological materials because the electrochemical process works at lower temperatures. The reinforcement of nanoparticles will improve the mechanical properties and may also improve the biological response. Drug incorporation may reduce the risk of post-surgery infection and even catalyze the growth of the bone,” says Eliaz.