Tag: seminar

Seminar: Vascularized Bone Grafts for Craniofacial Regeneration

sep5Biomedical Engineering Graduate Seminar: Warren Grayson, Ph.D. Assistant Professor, Biomedical Engineering, Johns Hopkins University; Friday, September 5 – 138 Fisher at 10:00 a.m.

Title: Vascularized Bone Grafts for Craniofacial Regeneration

The treatment of large bone loss due to congenital defects, trauma or cancer resection remains a huge clini-cal challenge. There are approximately one million fractures requiring bone transplantation annually in the US and it is predicted that within the next 10 years this number will significantly increase, particularly in per-sons over 50 years of age. Tissue engineering provides a viable means of obtaining ‘autologous’ bone grafts for the treatment of large bone defects. Successful application of tissue-engineered grafts however requires that we can couple the formation of de novo vasculature in tandem with new bone growth. Our lab has investigated methods for cultivating anatomically-shaped bone grafts in bioreactors and pre-vascularizing these grafts via co-culture techniques. More recent studies have examined the use of adipose-derived stem cells (ASCs) to engineer vascularized bone grafts that can be used to repair craniofacial de-fects. We have found that heterotypic interaction among endothelial and non-endothelial sub-populations mediate by growth factor effects can choreograph the formation of complex tissue grafts. These findings suggest the tremendous potential for using ASCs in concert with engineering techniques to provide clinically relevant vascularized bone grafts for the repair and regeneration of craniofacial bone loss.

This seminar is partially funded by the Visiting Women & Minority Lecturer/Scholar Series which is funded by the President’s Office and a grant to the Office of Institutional equity from the State of Michigan’s King-Chavez-Parks Initiative


Biomedical Engineering Graduate Seminar: Magnesium-Neodymium Alloys for Biomedical Applications

Biomedical Engineering Graduate Seminar:
Dr. Jan-Marten Seitz, Institut für Werkstoffkunde, Leibniz Universität Hannover, Garbsen, Germany
Friday, April 4 at 3:00 in U113 M&M

Title: “Development and Characterization of Magnesium-Neodymium Alloys for Biomedical Applications”
The aim of the presented study is to investigate and demonstrate the potential of neodymium additions as a substitute for rare earth (RE) misch-metal in magnesium alloys for biomedical applications. Here, the alloys LAE442, LANd442, ZEK100, ZNdK100, and Nd2 were manufactured and processed to evaluate their material characteristics in different states and to investigate the effects of Nd additions. To determine the mechanical characteristics of these alloys, tensile tests were initially carried out in the hot extruded state. Subsequent T5- and T6-heat treatments were con-ducted to reveal their effect on the alloys’ strength and elongation values. The general degradation behavior of the alloys in a 0.9% NaCl solution was investigated by means of polarization curves and hydrogen evolution. In addition, by using various in-vivo-parameters, a corrosion environ-ment was established to determine the alloys’ degradation in vitro. Comparing LAE442 and LANd442, a lack of corrosive stability could be ob-served while the mechanical strength remained constant in the latter alloy’s Nd substitution for the RE mischmetal. A contrary effect was deter-mined for the alloy ZEK100 compared with ZNdK100. In both substitutional approaches, heat treatment procedures could not align the substi-tutes’ material properties with the educts’ material properties. However, in the case of Nd2, which was initially chosen as relevant alloy to deter-mine the effects of Nd on Mg in a simple binary composition, excellent ductility and corrosion properties could be observed. This makes the alloy a promising candidate for use as resorbable implant material, especially in the field of stenting applications. Here, the enormous increase of duc-tility, promoted by an advantageous microstructural behavior under loadings, could be attributed to additions of Nd.

Biography: Within the past 5 years, Dr. Seitz has worked as a PhD Student and Scientist at Leibniz Universität in Hannover, Germany, with a focus on lightweight materials research and biomedical engineering applications. He developed process chains for resorbable Mg-implant applications such as stents, intramedullary nails, and sutures. This work included basic processes such as casting, hot-extrusion, heat treatment, drawing and coating procedures, as well as many analytical processes. The impact of different alloying elements on the mechanical and corrosive behavior of Mg in different conditions was one of the biggest challenges in this context. Besides the development of promising biodegradable Mg alloys, he also worked on the manufacture of thin wires from magnesium by means of extrusion and drawing processes. During an overseas stay at The University of Auckland, he developed polymer and ceramic based coatings for medical applications with magnesium and analyzed their structural behavior in a corrosive environment.