Metallic biomaterials are typically the choice for wear resistant parts in most biomedical devices towards load-bearing implants. However, concerns are growing related to metal ions in the body that can cause metallosis, and severe tissue and bone damage in some patients. Metallic devices offer greater motion, higher stability and higher than 99 percent reduction in wear debris compared to polymer components; however, use of these metallic implants dropped significantly in recent years primarily due to metal ion release concerns. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research to gain understanding on metal-ceramic composites that can reduce the release of metal ions in human bodies due to in situ formation of self-lubricating films at the contact surface. Results from this research can offer future direction to solve long-standing metal ion release problems in load-bearing implants such as total hip arthroplasty and total knee arthroplasty, which can increase life of implants' for patients of all ages.
In load-bearing implants, when two metal surfaces come in contact, there is wear induced damage that releases metal ions inside human bodies. The goal of this project is to minimize release of metal ions from metallic implants inside human bodies using self-lubricating ceramic based tribofilms. These films are formed in situ at the contact surfaces of metal-ceramic composites, and are similar to cartilage between the two hard articulating surfaces in load-bearing implants. The project will generate fundamental knowledge related to processing of metal-ceramic composites capable of forming self-lubricating films during articulation via laser based additive manufacturing. The research objective is to understand the influence of different amounts of calcium phosphates addition to titanium on mechanical and biological properties of titanium-calcium phosphate composites. To achieve this objective, first, titanium-calcium phosphate metal-ceramic composites will be processed using laser engineered net shaping with varying amounts of calcium phosphates, from 1 to 10 weight percent of titanium. Second, mechanical properties (such as tensile and compression strengths, and elastic moduli) of titanium-calcium phosphate composites will be measured under uniaxial loading using servo-hydraulic testing set-up. Third, wear resistance of these composites will be evaluated using flat-on-flat fully automated wear testing set-up. Finally, in vitro biological properties of these composites will be evaluated using human osteoblast cells at day 3, day 7 and day 11 in culture media.
