Complex Nanocomposites for Bone Regeneration

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DESCRIPTION (provided by applicant): This Bioengineering Research Partnership proposal is submitted by a multidisciplinary collaboration of scientists in the University of California (UC) system. The lead institution is Lawrence Berkeley National Laboratory, with component groups at UC Berkeley and UC San Francisco campuses. This BRP brings together expertise in materials sciences, chemistry, biology, and dental/medical science to begin the translational phase of this project. Our goal is to develop biomaterials for tissue engineering that will eliminate surgical risks and allow immediate return of function. We will develop and test new implant materials that can support mesenchymal stem cells and bone regeneration, by combining biomimetics with radically new design philosophies that consider anatomic and functional needs, customizing the scaffold to the skeletal defect. The ultimate goal is to develop a range of osteoinductive implant materials or scaffolds that function harmoniously with the surrounding native tissue. This long-term goal will provide materials for optimal repair of craniofacial and orthopedic skeletal defects that would otherwise require a bone graft from a second surgical site. First, hydrogels with varying mechanical responses and biodegradation rates will be synthesized. Different functional groups will be added to the hydrogel structure to template biomimetic mineralization of apatite and other biominerals-and to promote cell adhesion. Second, these materials, and others already developed for our current grant, will be used in the preparation of scaffolds with various compositions and architectures, including anatomically-inspired designs that considers both cortical and cancellous functional anatomy made by robocasting (3-D printing) and lamellar structures prepared using a novel technology developed in our laboratory based on freeze-casting of suspensions. Third, the addition of diverse functional capabilities to these porous scaffolds will be systematically explored. Materials deemed to display optimal mechanical responses will be tested in cell culture and then in vivo in mice, using standardized bone formation assays that allow assessment of the rate and extent of new bone formation. Based on these results, we will select scaffolds that have the greatest translational potential. These will be tested in combination with autologous multipotent stem cells for the ability to promote bone formation in established medium-sized (rabbit) and large-sized (mini-pig) animal models utilizing a consistent protocol of biomechanical and biological assays that will also serve to asses key biological process that determine scaffold integration. Successful completion of these studies will result in the identification of new materials suitable for testing for the repair of craniofacial and orthopedic skeletal defects in humans. The present standard of care for such defects may be altered to eliminate bone grafts, decrease risks to patients, improve quality of life, and increase the armamentarium of the clinician.