Carbon nanotube coating on titanium substrate modified with TiO₂ nanotubes

A combination of carbon nanotubes (CNTs) and titanium (Ti) modified with TiO₂ nanotubes (TiO₂ NTs) was fulfilled with the aim of improving bioactivity of Ti implant. First, well-ordered TiO₂ NTs were prepared by the electrochemical anodization of Ti in an ethylene glycol electrolyte containing 1 wt% NH₄F and 10 wt% H₂O at 20 V for 50 min, followed by annealing. Then, the carboxylated CNTs were coated onto the TiO₂ NTs using electrophoretic deposition (EPD) technique. The growth of hydroxyapatite (HA) on the samples was investigated by soaking them in simulated body fluid (SBF). The result showed the CNTs-coated Ti with the modification of TiO₂ NTs (CNTs-TiO₂ NTs) was more efficient to induce HA formation than the CNTs-coated smooth Ti (CNTs-Ti). The vitro cell response was evaluated using osteoblast cells (MC3T3-E1). The good cell proliferation and strong cell adhesion could be obtained on the CNTs-TiO₂ NTs. These results indicated that CNT coating on the Ti modified with TiO₂ NTs could be potentially useful for the periodontal ligament combination on dental implants.