Enhancement of osteoblast function upon electrical stimulation on anodized titanium

Currently used titanium implants in orthopedics have a limited lifespan of only 10-15 years. The limited ability of the titanium implant to remain bonded to juxtaposed bone is one of the leading reasons for implant failures. In order to improve cytocompatibility properties, it has been proposed to modify titanium through anodization to create a nanotubular topography. Additionally, electrical stimulation has been used in orthopedics to heal bone non-unions and fractures. In this study, these two approaches were combined as the efficacy of electrical stimulation to promote osteoblast density on anodized titanium was investigated. To examine this, a 5-day osteoblast proliferation experiment was conducted with 1 V, 5 V, 10 V and 15 V constant bipolar pulses. Results showed that under electrical stimulation, osteoblast proliferation on anodized titanium was enhanced at lower voltages compared to what was observed on conventional titanium. Moreover, compared to non-stimulated conventional titanium, osteoblast proliferation was enhanced 72% after 5 days of culture on anodized nanotubular titanium at 15 V of electrical stimulation. Additionally, osteoblasts on anodized nanotubular titanium not only showed a more well-spread cell morphology, but also expressed more filipodia on their surfaces than the osteoblasts on conventional titanium. Cumulatively, these results suggest that coupling the positive influences of electrical stimulation and nanotubular features on anodized titanium may improve osteoblast responses necessary for enhanced orthopedic implant efficacy.