Grants We Funded

Abstract
Reconstruction of the ear for congenital abnormalities such as microtia or acquired auricular deformity is particularly challenging. The use of shaped autologous rib cartilage demands tremendous technical expertise, causes significant morbidity, and requires pediatric patients to wait several years after birth for treatment. Synthetic materials used for ear reconstruction do not sufficiently mimic the mechanical properties of ear cartilage and are associated with higher rates of infection and extrusion. Given these challenges, there is keen interest in tissue engineering approaches to produce an anatomically shaped ear cartilage framework for transplantation. Previously, we reported on the use of 3D photogrammetry combined with CAD/CAM techniques to design molds with patient-specific geometry for the generation of ear-shaped implants. These molds, in combination with our tissue injection molding techniques and use of high-density collagen gels, enabled the rapid fabrication of implants seeded with bovine auricular chondrocytes in the shape of pediatric human ears. Molded high-density collagen gels are sufficiently stiff to maintain their shape in an animal without the use of materials for internal support. When implanted subcutaneously and harvested after 6 months, implants demonstrated effective permanence; ear implants maintained their shape, demonstrated mechanical functionality indistinguishable from native auricular cartilage, and the seeded chondrocytes produced tissue with copious amounts of type II collagen, proteoglycan, and elastin. Despite these extremely promising data, there remain challenges to surmount prior to clinical application of this technology; specifically, it will require validation of the process using human cells, and a feasible approach to overcome the large 250 million human chondrocyte requirement needed to create a full sized human ear. In this project, we aim to employ a novel cell sourcing strategy using human auricular chondrocytes and human mesenchymal stem cells in vivo in nude mice to determine the ideal minimal cell ratio to produce elastic cartilage. Subsequently, we seek to fabricate full sized human ears with human auricular chondrocytes for in vivo implantation in nude rats. Upon the successful completion of these specific aims, we will have fabricated the world's first full scale, high anatomic fidelity human auricular scaffold and be ready to use this technology for immediate application in the clinic.

Biography
Dr. Jason Spector is a nationally recognized clinician, researcher and educator. He holds two patents, and has been an integral part several Cornell University-Weill Cornell Medical College translational research teams. He participates in the NIH and Howard Hughes Medical Institute sponsored Clinical Summer Immersion for Biomedical Engineering Program, mentoring engineering doctoral students. Since 2007, he has been a lecturer at Cornell University's Biomedical Engineering Science and Technology course, "Approaches to Problems in Human Needs." Dr. Spector serves as an Ad-Hoc reviewer for six prestigious medical journals, and has presented at national and international medical meetings. He recently served as Moderator of the Emerging Technologies Section, at the American Surgical Congress in 2011.