Engineering a new biomaterial for stem-cell mediated bone regeneration

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DESCRIPTION (provided by applicant): In a 4-year training/career development program for this investigator who has a strong background in biomaterials science and more recent clinical training in orthodontics, three specific aims are: (1) the development of further skills in tissue engineering involving a porous scaffold for ingrowth of tissues, extending previous experience and expertise in this area; (2) new capabilities in use of MAPC (multipotent adult progenitor cells) in tissue engineering of this type; and (3) clinical research skills based on longitudinal follow-up of patients treated for various types of dentofacail and craniofacial deformities. The overall longterm goal is to develop a replacement for both soft and hard tissue defects in the craniofacial complex (and elsewhere in the body). The short-term goal is to determine whether a biomimetic hydroxyapatite-gelatin (HAP-GEL) nanocomposite can serve as a load bearing scaffold to carry MAPC and grow bone. The training program is built around interaction with four mentors, related to each specific aim above, and participation in courses and seminars developed in the clinical scientist program at UNC. The mentors are Drs. Mitsuo Yamauchi (application of collagen cross-linkage in scaffold development for tissue engineering), Wei-Shou Hu (stem cell biology) and Leaf Huang (application of growth factors) and William Proffit (longitudinal studies of patients requiring orthognathic surgery for correction of dentofacial and craniofacial defects). Proposed work toward the short-term goal involves (1) cultivation of MAPC on a nanocomposite HAPGEL matrix so that MAPC differentiate into bone cells; (2) design of the HAP-GEL matrix to allow controlled release of growth factors to produce multiple lineages of MAPC differentiation and maximize penetration of MAPC into the matrix; and (3) design of the matrix to maximize the mechanical strength of the MAPCcarrying scaffold so that it could become a load-carrying graft. Preliminary data show promising interactions between osteoblasts and the HAP-GEL matrix, and it appears that this offers a highly favorable way to offer MAPC-based therapy. The significance of this work is that it can provide a new way to replace missing tissues in patients with congenital, developmental or trauma-induced deformities. With a graft material of this type, it should be possible to eliminate multiple surgeries in the treatment of critical-size cranial and facial defects.