Calcium-Phosphate Gelatin Brick-Mortar Materials Templated by Chitosan Fabricated by Enzymatic Mineralization

For bone regeneration biomimetic materials, coordinating their mechanical properties and desired biological activity is a key issue, because they are often difficult to maximize at the same time. This makes it one of the main challenges to explore the effective combination of these two properties in bulk materials. Inspired by the “organic–inorganic” brick-and-mortar structure of nacre, this paper combines chitosan (CS) and gelatin (Gel) mixed solutions via bidirectional freezing method and thermoplastic molding technology to form an organic matrix, which then specifically binds with enzyme (EAP-ChBD) to achieve enzymatic mineralization. Among them, enzymatic catalysis promotes organic phosphate groups to release inorganic phosphate ions, which directionally deposit in the organic layered scaffold. Finally, enzyme-induced biomimetic mineralization forms hydroxyapatite (HAP) that combines with the matrix, successfully preparing a hierarchical bulk bionic biomposite material. This composite material possesses high strength and Young’s modulus─with strength increasing from the initial 110 to 240 MPa and modulus rising from 6 to 26 GPa. In addition, the biological activity of its components in theory needs to be further studied to verify its supporting effect on bone regeneration, which suggests that the material may have potential value for further exploration in bone repair.