Description
- Abstract:
- Titanium, titanium alloys, and cobalt-chromium alloys are widely used in orthopedic applications. To promote the osseointegration of implants into juxtaposed bone, an electrochemical surface modification method, anodization, was utilized in the present study to create biologically-inspired titania nanotubular structures on currently-used titanium implant surfaces. This anodization technique was also applied to Ti6Al4V and a CoCr alloy. Characterizations of such anodized Ti, Ti6Al4V and CoCr demonstrated increased nano-roughness, increased surface wettability, and increased surface energy compared to their non-anodized equivalents. Cytocompatibility tests with osteoblasts and chondrocytes showed enhanced short term and long term cellular responses on anodized Ti, Ti6Al4V and CoCr compared to their non-anodized counterparts for the first time. Importantly, the underlying mechanisms of this observed increased cellular responses were elucidated in this study by greater amounts of vitronectin and fibronectin (proteins that mediate osteoblast and chondrocyte adhesion) preadsorption on anodized compared to unanodized surfaces. The anodized titanium possessing nanotubular structures was also studied for novel metallic drug delivery applications. For this, anodized titanium was functionalized with hydroxyl, amine, or methyl groups to possess varied surface energy properties. Antibiotics (such as penicillin/streptomycin and penicillin G sodium salt) were loaded into such anodized titania nanotubes via a physical adsorption method. Characterization of drug release behavior showed that the most hydrophilic anodized titanium with hydroxyl groups released the most amounts of antibiotics after two days. Antibiotics were loaded onto anodized titania nanotubes via a co-precipitation method that combined antibiotics with calcium phosphates. Drugs loaded onto anodized titanium implants using this method exhibited a prolonged release of up to 3 weeks. Antibiotic-loaded anodized titanium further inhibited S. epidermidis (the primary bacteria which causes orthopedic implant infection) attachment but did not inhibit osteoblast adhesion. In summary, these results indicated that anodization can be used as a quick, inexpensive platform to modify numerous orthopedic implants to possess nanofeatures and, thus, increase the responses of bone and cartilage cells. Further, anodizing titanium to possess nanotubular structures can be an innovative metal-based drug delivery system to further ensure the efficacy of orthopedic implants.
- Notes:
- Thesis (Ph.D.) -- Brown University (2009)
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Citation
Yao, Chang,
"Designing novel orthopedic implants based on an anodization platform"
(2008).
Biomedical Engineering Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0VT1QC3
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Biomedical Engineering Theses and Dissertations
Theses and Dissertations for the Biomedical Engineering department....