The aim of this research program is to develop a functionally graded Hydroxyapatite (FGHA) coating for orthopedic and dental implants with a tailored release rate of an antimicrobial component. In this case, the antimicrobial element will have a higher release rate together with the mostly amorphous layer at the surface of the coating immediately after implantation, and its release rate will gradually decreases with increasing crystallinity of the coating. Furthermore, the proposal aims to increase the service-life of an orthopedic/ dental implant by creating coatings that forms a strong, long lasting bond not only with the juxtaposed bone, but also with the metal substrate. All this will translate into the patient receiving an orthopedic or dental implant, with a superior bioactive coating with an integrated antimicrobial component. As a result, the patient could return to a normal lifestyle sooner with the reduced antibiotics intake along with less risk of infection and its subsequent complications.
The proposed study investigates a new coating material with tailored dissolution rate that can match with bone growth together with gradually released antimicrobial components that can have a great impact on the development of the next generation of orthopedic and dental implants with improved durability, along with better biological responses. The education plan involves four complementary initiatives including: interdisciplinary research based on collaboration between three different departments at two university in US and the Japan National Institute of Materials Science, new graduate course development on Advanced Materials including Biomaterials, team work between undergraduate and graduate students and a special attempt to hiring female, underrepresented and disabled students
The project focus was on processing and characterization of a smart coating for biomedical implants. When a dental or orthopedic implant is placed in the body, there a chance of rejection and infection. In this case, we introduced a technique to apply a thin layer of functionally graded coating on the surface of a metal implant with a chemical composition similar to the bone. As the result, the bone will accept the implant easier and start building on top of that. The top portion of the coating dissolves into the body shortly after the surgery and releases calcium and phosphate to encourage bone growth. The lower portion of the implant will stay in place for a longer period of time and provide stability for the implant. The speed of dissolving of smart coating can also be tailored to an individual patient based on how quickly their bones grow. The last but not least technical achievement of the project is for drug delivery in which small amount of antibacterial elements are added to the coating and it can be released while the coating is dissolved in the body and prevent infection, so the patient will not need to take additional oral antibiotics that may impact his/ her entire body. The project aimed to help the patient receiving a biomedical or dental implant to recover faster after the surgery. Two inventions were filed based on the new technology and a small company licensed the patents. The education outcome of the project was on educating two PhD students, three undergraduate researchers, add a large section on a graduate course on Biomaterials that is being offered every fall for on-campus and off-campus students on line. There has been nine technical articles published in very highly cited journals, a collaboration with Japan National Institute of Materials Science, Oak Ridge National Lab, and between the two institutions of PI and Co-PI, which helped the students involved to learn in an interdisciplinary environment. It is also notable that one 5th grade teacher was trained in PI’s lab during summer and the PI together with the teacher could develop a new elective course that presented in an elementary school in fall 2011. The students’ pre- and post-assessment knowledge on various type of engineering went from about 21% average to over 60% average. The title of the elective course is "Introduction to Engineering for Boys and Girls". This course is scheduled to be presented every year in that elementary school in Raleigh. Figure 1 TEM images of cross section of coatings FGHA-Ag1, FGHA-Ag2 and FGHA-Ag3. a-1, b-1 and c-1 are images showing entire thickness of coatings on Ti whereas a-2, b-2 and c-2 are closer observation of coating region near interface.
