North Carolina A&T State University
NSF Engineering Research Center + Bioengineering Joint Seminar Series


Effect of Rare Earth Elements on Mg-based Alloys as Stent Materials


Dr. Donghui Zhu
Assistant Professor of Bioengineering
Chemical, Biological and Bioengineering
NC A&T State University



11 AM – 11:50 AM – Friday, November 8, 2013
McNair Hall Auditorium – College of Engineering



Rare earth (RE) elements can enhance the mechanical strength of different metal alloys. However, it is still unclear how RE elements will affect the magnesium (Mg) alloys intended for stent materials as a whole. In this study, we evaluated MgZnCaY-1RE, MgZnCaY-2RE, MgYZr-1RE, and MgZnYZr-1RE alloys for cardiovascular stent applications in regards to mechanical strength, corrosion resistance, hemolysis, platelet adhesion/activation, and endothelial toxicity and biocompatibility. The mechanical properties of all Mg-RE materials were significantly improved over the pure Mg control. DC potentiodynamic polarization showed that the corrosion resistances of all Mg-RE alloys were at least 3-10 times higher than that of pure Mg control. Hemolysis testing revealed that all the materials were non-hemolytic, while little/mild platelet adhesion was found on all material surfaces. No significant cytotoxicity was observed in Mg-RE alloys cultured with primary human aorta endothelial cells for up to seven days. Direct endothelialization testing showed that Mg-RE alloys possess significantly better capability to sustain endothelial cell attachment and growth compared to the pure Mg control. The results demonstrate the promising potential of these Mg-RE alloys for stent material applications in the future.


About the Speaker:

Dr. Don Zhu is an Assistant Professor of Bioengineering at North Carolina A&T State University where he directs the cardiovascular tissue engineering lab.  He is also an investigator associated with the NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, with focus on the ERC Green Team’s biocompatibility thrust.  Don’s primary research interest includes cardiovascular stents development, neurovascular tissue engineering, and bio-safety of implantable medical devices.  Don is recipient of several research grants from NIH and State of North Carolina.