Enhanced bone regeneration on the fusion protein tethered scaffolds

Abstract

Event Abstract Back to Event Enhanced bone regeneration on the fusion protein tethered scaffolds Minsil Kang1, 2, Khaliun Boldbaatar1, 2, Eun-Jung Lee1, 2, Roman A. Perez1, 2 and Hae-Won Kim1, 2, 3 1 Dankook University, Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicin, Korea 2 Dankook University, Institute of Tissue Regeneration Engineering, Korea 3 Dankook University, Department of Biomaterials Science, College of Dentistry, Korea Introduction: Developing scaffolds have the surface tailored with fusion proteins is an important issue in bone tissue engineering. In general, ECM molecules are coated on scaffolds showing enhanced biological processes, although their limited stability may limit their applications. The proteins that mimic the extracellular matrix (ECM) show enhanced biological processes, such as adhesion and differentiation of stem cells. Here, we synthesized a multifunctional fusion protein FN-OCN-CBD (Fibronectin-Osteocalcin-Collagen binding domain), and then immobilized the protein on the surface of 3D polymeric scaffolds, aiming to provide initial attachment motif together with osteogenic differentiation signaling. Materials and Methods: Biopolymer (polycaprolactone) scaffolds were produced by the robocasting method with a macrochanneled pore structure. The surface of the scaffolds was coated with the solutions made of fusion protein and collagen. The degradation and stability of the proteins were assessed by the Sirius red assay. Mesenchymal stem cells (MSCs) were used to analyze the initial cellular adhesion, proliferation and osteogenic commitment on the protein tethered scaffolds. Confocal images were used to observe the cell morphology. In vivo studies were performed in a rat calvarial defect model over a 6-week period. The bone formation was analyzed by means of µ-computed tomography and histology. Results and Discussion: Collagen-derived fibrillar network structure was produced evenly on the surface of the scaffolds, allowing tethering the fusion protein in a homogenous fashion on the scaffold. The stability of the fusion protein was well preserved over a long period of time. MSCs showed excellent adhesion behaviors, with enhanced anchorage rate and focal adhesions through the interaction with the FN adhesive domain. The gene and protein expressions of cells were substantially higher on the protein tethered scaffolds when compared to those on the unmodified scaffolds, implying that the cells secreted greater level of bone-associated ECMs. The in vivo findings at 6 weeks implantation in calvarial defect showed significantly higher bone volume and bone surface density on the protein tethered scaffolds. Conclusion: The multifunctional protein tethered scaffolds were effective in stimulating the initial adhesion and osteogenic differentiation of MSCs in vitro as well as the bone formation in vivo. The scaffolds are considered to provide bio-interface conditions favorable for bone tissue engineering. National Research Foundation, Republic of Korea; Priority Research Centers Program (No. 2009-0093829); Global Research Lab Program (2015032163)