The utility of 3D nanostructured polyglycolic acid fibers for novel bone regenerative medicine

Autologous and artificial bone grafts are widely applied for alveolar bone reconstruction. However, as concerns regarding invasiveness, safety, and efficacy persist, the improved novel regenerative materials are expected. This study focuses on the bone regenerative potential of three-dimensional (3D) nanofiber-based polyglycolic acid (nPGA), whose capacity for bone regeneration remains unclear. Four types of 3D PGA fibrous matrices with different fiber diameters and surface densities were used. The cell affinity, proliferative capacity, and osteogenic differentiation potential of the nPGA matrices were evaluated using human dental pulp stem cells (DPSCs). The effects of nPGA on bone regeneration were also investigated using an in vivo rat calvarial bone defect model. The cellular responses to the PGA matrix clearly differed depending on the structural properties of the PGA fibers. Cell engraftment was significantly enhanced in the nPGA group compared to the conventional PGA group. DPSCs exhibited a time-dependent proliferation on the nPGA matrices. Scanning electron microscopy revealed cellular extensions aligned along the 3D microfiber architecture. Moreover, the osteoinductive assays demonstrated that DPSCs possessed osteogenic differentiation potential on nPGA scaffolds. Histological evaluation revealed new bone formation in the nPGA-transplanted group. Immunohistochemical staining of CD31 demonstrated that neovascularization also occurred adjacent to the newly formed bone in this group. The 3D nPGA matrix characterized by finer fibers and low surface density exhibited a remarkable cell affinity and an effective scaffold function in osteogenesis, suggesting that it could be useful as a novel medical material in bone regenerative medicine.