The objective of the research is to understand the interrelationship between the interface modification and the final performance of the HA coating. Such coatings should have a strong bonding strength, stable interface, superior corrosion resistance and excellent biocompatibility suitable for orthopedic and dental applications. The proposed approach is to modify the Ti alloy surface prior to HA coating. A multifunctional compliant multi-layer will be applied to the surface of the Ti alloy, which consists of a FeCrAl thin film bottom layer, a dense, adherent alpha-alumina subscale, and a nano-whisker alumina top layer. Futhermore, nano HA coatings will be applied onto the surface of the compliant layer using either electrophoresis or biomimetic assembly. Both coating techniques will be explored as model systems for comparison.
The proposed project has a broader societal impact on various scientific disciplines. Not only will it deliver a new type of implant material with superior performance for better healthcare, but will also give new insights to overcome the long-standing problems of poor metal-ceramic bonding. The nano-engineered metal surface could also provide a new template for micro-electro-mechanical systems (MEMS) and nano-electro-mechanical systems (NEMS) applications, such as sensors and actuators for harsh environment and drug delivery devices. This project will result in the training of a number of graduate and undergraduate students in the area of biomaterial interface studies, while exposing them to multidisciplinary inter-university (UConn-UCF) collaboration. In addition, we will perform K-12 outreach to get high school teachers and students, especially female and under-representative minorities, excited about engineering research.
Over 10 million Americans are currently carrying at least one major implanted medical device in their body. The medical device market in America has a turnover of $50 billion per year, and it still grows every year. More than forty percent of the implants involve the use of metallic implants. Unfortunately, nearly all metallic materials are bioinert, so they are consequently not osteoconductive leading to no surface continuity. To enhance the integration between the implant and natural bone, a novel biomimetic apatite coating with a graded microstructure has been created on the surface of metallic implants, which features a dense bottom structure to form a strong bond with the metallic implant, and a porous surface to facilitate cell attachment and bone growth. The coating not only forms a strong bond to the metallic substrate, but also improves the corrosion resistance of the substrate. It is believed that the apatite coated implants will be suitable for broader orthopedic applications. This project has also resulted in the training of a number of graduate and undergraduate students in areas of surface treatment of metallic substrates, biomimetic apatite coating, mechanical testing, and in vitro cell culture. In addition, we have published one book chapter, and numerous referred journal papers and conference proceedings with the findings from this project. The results of this project were also presented at different occasions, such as national and international conferences, seminars to professionals, and graduate, undergraduate and high school students, Engineering open houses, and Materials Science and Engineering Program demonstrations.
