Soldiers are often called to duty and sent overseas to dangerous combat areas. Many return home with severe combat wounds and injuries that lead to amputations. Between 2001 and 2010, over a thousand major limb amputations were performed on US soldiers, including 816 during Operation Iraqi Freedom, 217 during Operation Enduring Freedom, and 189 from unaffiliated conflicts. The occurrence of injuries resulting in amputations for wounded soldiers has risen over the years as counterinsurgency strategies shifted; requiring soldiers to be on foot. Though new improvements in prosthetic devices are phenomenal, none compare to the mobility and functionality of the original limb.
Dr. Xiaojun Yu
Dr. Xiaojun Yu, Associate Professor of Biomedical Engineering at Stevens Institute of Technology, envisions a future technology that fully regrows nerves and restores function to damaged limbs, thus eliminating the need for amputation. With a recent grant awarded by the Department of Defense, Dr. Yu is working to improve nerve regeneration research and help wounded soldiers regain mobility.
Dr. Yu will be concentrating on designing and developing a scaffold, a biological substitute that is used as a basis to seed and facilitate new nerve cells. By creating a biodegradable scaffold that mimics the structure and morphology of natural nerves, damaged nerve tissue could be augmented or replaced surgically.
“The scaffold provides an initial basis to grow the nerve cells, and slowly degrades as new nerves form until it is completely replaced by natural tissue. The graft system is composed of a composite of nanofibers that are structured to provide optimal conditions for mechanical stability and cell growth,” says Dr. Yu. “Bone marrow cells from the same patient provide the initial cells on the scaffold, minimizing the risk of rejection from the host.”
“Clinical use of the scaffold system could decrease recovery time for soldiers following severe injuries, which would lead to a lower demand on rehabilitation services and less medical costs for the military overall,” says Dr. Philip Leopold, Director of the Chemistry, Chemical Biology, and Biomechanical Engineering Department. “Most importantly, Dr. Yu’s research has the potential to have a profound effect on the lives of injured soldiers.”
The current “gold standard” treatment for damaged nerves is an autograft, where a segment of nerve is taken from another site on the patient and implanted at the injury site. While autografts effectively regrow nerves, there is a risk of causing additional damage at the donor site. Also, the donor site does not always have long enough nerve tissue to replace the injured nerve. Other commercial scaffold solutions utilize a simple collagen- or polymer-based tube and are not designed optimally for nerve regeneration, therefore, tissue growth is very slow and functional recovery is not guaranteed. Dr. Yu’s scaffold has dedicated structures to maximize nerve regeneration. His innovation offers a safer and more effective scalable alternative to currently available technologies.
“On a broader scale,” says Dr. Michael Bruno, Dean of the Charles V. Schaefer, Jr. School of Engineering and Science, “Dr. Yu’s work not only provides the framework for innovative therapy treatments that will improve the lives of wounded soldiers but also offers doctors the potential for regenerating many other types of tissues for noncombat-related injuries.”
Dr. Yu is assisted by Ph.D. candidate Wei Chang. Originally from Taiwan, Mr. Chang came to Stevens in 2006 to pursue a Master’s of Science in Materials Engineering. He became interested in biomedical engineering when he took the Introduction to Nanotechnology course taught by Dr. Yu. After entering the Biomedical Engineering doctoral program under Dr. Yu’s guidance, Mr. Chang spent a lot of time learning biology and physiology to supplement his materials engineering expertise. “Dr. Yu has been a fantastic mentor,” says Mr. Chang. “He trains his students to think critically for themselves in preparation for the real world.”
By combining his materials engineering background with biomedical engineering, he is able to develop innovative and effective new nerve scaffolds. After completing his Ph.D., Mr. Chang plans to continue developing nerve scaffolds and pursue a patent on the design. He hopes to conduct tissue engineering research at a biotech or pharmaceutical company.
Dr. Yu’s other research activities include investigation of cell and material interactions in 2D, 3D and in bioreactors, development of controlled release systems for the delivery of growth factors and drugs, and manipulation of the microenvironment for stem cell proliferation and differentiation. He is a member of the Society for Biomaterials, and the Materials Research Society and has contributed many journal articles and conference proceedings. He has also received the Early Career Translational Research Award in Biomedical Engineering (Phase I & Phase II) from the Wallace H. Coulter Foundation, and a research grant from the AO Foundation for supporting his work in developing novel tissue engineered scaffolds for improving bone healing.
For more information about this research and other activities in health care at Stevens, please contact Dr. Peter Tolias.
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