Dr. Daniel S. Oh., College of Dental Medicine, Columbia University Medical Center; Founder, DSO Bone Research Institute, USA

Speech Title: Innovative Bone Regeneration in Critical Segmental Defect via Bone-like Scaffold

Abstract: An effective, long-term treatment of critical-sized bone defects remains challenging for surgeons and patients. Three key processes within the bioengineering construct, active endogenous cells recruitment into scaffold, homogenous distribution, and inhabitance together with a pro-angiogenic microenvironment is crucial for functional bone restoration. Accordingly, we present a biogenic microenvironment scaffold (BMS) that fosters infusion of the scaffold with patient’s own cells and stromal elements. Hydroxyapatite-based BMS is composed of three-level basic structures; First, porous trabecular network that is like human trabecular (250-400 μm). Second, micro-sized channels (25-70 μm) within each trabecular septum. Third, the surface of each septum has nano-sized pores that boost immobilized cells to anchor. Multi-scale μm-size channels exhibit highly effective fluid sucking property that stimulate cell immobilization. Our study showed a bone-like scaffold that actively induces mobilization of endogenous cells and fluids from host body by capillary action via micro-channels, thereby eliminating the need of pre-loading cells and growth factors. A 2 cm-long segmental defect was created in a beagle tibia and restored the defect with BMS. Microscopically, BMS seamlessly integrated with the host bone and completely bridged the defect by forming a new cortical and trabecular bone, indicating perfect reunion and reconstruction segmental defect by BMS. Micro-CT images show that the original bone contour was fully restored at 8 weeks. Osteogenesis and vasculogenesis were clearly developed within the micro-channels as well as other spaces of BMS. Cortical bone along the outer of scaffold was completely regenerated, which was evidenced by the presence of the haversian system. Giving these findings, we posit that BMS provides a sufficient biogenic microenvironment for bone regeneration in massive skeletal defects and considered as a ready-to-use synthetic bone graft.

Keywords: Biogenic Microenvironment Scaffold, Capillary Action, Segmental Defect