A Combination of Biphasic Calcium Phosphate Scaffold with Hyaluronic Acid-Gelatin Hydrogel as a New Tool for Bone Regeneration

A novel bone substitute was fabricated to enhance bone healing by combining ceramic and polymer materials. In this study, Hyaluronic acid (HyA)-Gelatin (Gel) hydrogel was loaded into a biphasic calcium phosphate (BCP) ceramic, and the resulting scaffold, with unique micro- and macroporous orientation, was evaluated for bone regeneration applications. The fabricated scaffold showed high interconnected porosity, with an average compressive strength of 2.8±0.15 MPa, which is usually recommended for cancellous bone substitution. In vitro cytocompatibility studies were conducted using bone marrow mesenchymal stem cells. The HyA-Gel-loaded BCP scaffold resulted in a significant increase in cell proliferation at 3 (p<0.05) and 7 days (p<0.001) and high alkaline phosphatase activities at 14 and 21 days. Furthermore, the in vivo studies showed that the implanted HyA-Gel-loaded BCP scaffold begins to degrade within 3 months after implantation. Histological sections also confirmed a rapid new bone formation and a high rate of collagen mineralization. A bone matrix formation was confirmed by positive immunohistochemistry staining of osteopontin, osteocalcin, and collagen type I. In vivo expression of extracellular matrix proteins demonstrated that this novel bone substitute holds great promise for use in stimulating new bone regeneration.