Hydroxyapatite deposition onto nanoporous titanium dioxide and assessment of bone cell growth and proliferation

Titanium (Ti) and its alloys are being used as implant materials in many orthopedic applications. To render these materials bioactive, Ti is coated with hydroxyapatite (HA). This work reports an innovative method for depositing crystalline HA onto nanotubular titanium dioxide (TiO2). Alkaline treatment prior to HA deposition provided a good template for the nucleation of HA inside the nanopores and heat treatment after HA deposition increased interfacial bond strength. To assess biocompatibility, human embryonic palatal mesenchyma (HPEM) cells were applied to HA coated Ti disks and placed in culture. Scanning electron microscopy as well as measurements of protein production and mitochondrial dehydrogenase activity confirmed HEPM cell growth and proliferation on the disks, and alkaline phosphatase activity, a measure of cell maturation, increased. Therefore, the HA coated Ti sample not only has a superior interfacial bond strength but also supports the growth and maturation of preosteoblasts.