Assistant Professor Batur Ercan
Department of Metallurgical and Materials Engineering
Middle East Technical University
Email: baercan [at] metu.edu.tr
Batur loves to read National Geographic, watch documentaries, cook (specifically Mediterranean food), and go to the gym.
The current 15-20 year life-span of titanium-based orthopedic implants has been a challenging problem. Limited cytocompatibility properties and osseointegration of implants to surrounding bone has been proposed as one of the leading causes of such limited lifetimes. Over the past decade, nanotechnology has been proposed to improve the lifespan of many biomedical devices, including orthopedic implants. Specifically, to improve the cytocompatibility properties of currently used titanium orthopedic implants, nanotechnology has been used to create nanofeatured thin oxide films (through anodization) on titanium surfaces. In addition to this approach, a theraupedic method to heal bone fractures through electrical stimulation (which is FDA approved) has also been investigated. Here, I studied the coupling affect of such nanotechnology approaches and electrical stimulation. The results showed that compared to unstimulated conventional titanium, bone forming cell (osteoblast) proliferation and long-term functions (alkaline phosphatase synthesis, collagen type I synthesis and calcium deposition) were improved both upon creation of an anodized nanotubular titanium film and biphasic electrical stimulation. Moreover, anodized nanotubular titanium surfaces showed a decrease in fibroblast cell adhesion/proliferation compared to conventional titanium surfaces, which can reduce implant failures due to fibrous tissue formation around orthopedic implants. One another advantage is that anodized nanotubular titanium also showed enhanced resistance to bacteria (Staphylococcus aureus and Staphylococcus epidermidis) colonization, which can form a biofilm on the implant and potentially lead to implant failure. Upon electrical stimulation, decreased bacteria density was observed on the anodized surfaces compared to conventional ones. Changing the nanotube dimensions further decreased the bacteria colonization on these surfaces. Most importantly, when electrical stimulation was combined with anodized nanotubular titanium features, the beneficial effects (enhancement in bone cell functions and reduction in biofilm formation) were improved the best. Therefore, coupling the positive effects of anodized nanotubular titanium topographies with currently used theraupedic electrical stimulation is a promising method for bone-tissue engineering applications.