Magnesium Calcium Phosphate as a Novel Component Enhances Mechanical/Physical Properties of Gelatin Scaffold and Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells

Biodegradable gelatin sponges incorporating various amounts of magnesium calcium phosphate (MCP) were introduced and the in vitro osteogenic differentiation of rat bone marrow mesenchymal stem cells (MSCs) in the sponges was investigated. The MCP was added to the gelatin sponges at 0, 25, 50, 75, and 90 wt%. The pore sizes of the gelatin sponges ranged from 143 to 154.3 mu m in diameter and the porosity percentage was 34.3-50.1%. The compression modulus of the sponges and the resistance to the volume change significantly increased with increases in the amount of MCP. When seeded into the sponges by an agitating method, MSCs were distributed throughout the sponges. Following the incubation of MSCs in the gelatin sponges, a significantly higher cellular proliferation and alkaline phosphatase activity was observed in the gelatin sponges incorporating higher MCP contents. On the other hand, the osteocalcin content of MSCs seeded in the gelatin sponges incorporating no or low MCP showed a significantly higher levels in comparison with the MSCs seeded in the gelatins incorporating high MCP. These findings indicate that the MCP incorporation maintained the pore size and porosity percentage of the gelatin sponges and enabled the sponge to achieve mechanical reinforcement as well as promoting MSC proliferation and osteogenic differentiation.