(807e) Growth Factor Release From Polyelectrolyte-Modified Titanium and Titania Nanotube Surfaces

Polyelectrolyte coatings have been shown to be a promising option for modification of orthopedic implant surfaces to improve osseointegration and implant durability. In addition to modifying the chemical and physical properties of an implant suface, polyelectrolyte coatings are also capable of release of biologically relevant molecules. In this work, polyelectrolyte multilayer coatings based on poly(methacrylic acid) and poly-l-histidine were formed on anodized titanium surfaces with adsorbed bone morphogenetic protein 2 (BMP-2) or basic fibroblast growth factor (FGFb). These coatings were capable of sustained release of growth factor, with BMP-2 and FGFb exhibiting approximately identical release profiles. Cell culture on growth factor-eluting surfaces was more effective for osteoblasts/BMP-2 than for fibroblasts/FGFb. By adjusting deposition pH or the addition of a salt, denser or thinner multilayer coatings could be formed. In this way, processing can be used to control the release profile. Polyelectrolyte multilayer coatings were also formed on titania nanotube arrays, which enhanced the amount of growth factor that could be released from the nanotubes in a sustained manner.