Hierarchically microporous/macroporous scaffold of magnesium–calcium phosphate for bone tissue regeneration
Hierarchically 3D microporous/macroporous magnesium–calcium phosphate (micro/ma-MCP) scaffolds containing magnesium ammonium phosphate hexahydrate [NH4MgPO4·6H2O] and hydroxyapatite [Ca10(PO4)6(OH)2] were fabricated from cement utilizing leaching method in the presence of sodium chloride (NaCl) particles and NaCl saturated water solution. NaCl particles produced macropororosity, and NaCl solution acted as both cement liquid and porogens, inducing the formation of microporosity. The micro/ma-MCP scaffolds with porosities varied from 52 to 78% showed well interconnected and open macropores with the sizes of 400–500 μm, and degradation of the scaffolds was significantly enhanced in Tris–HCl solution compared with macroporous MCP (ma-MCP) and corresponding calcium phosphate cement (CPC) scaffolds. Cell attachment and proliferation of MG63 on micro/ma-MCP were significantly better than ma-MCP and CPC scaffolds because of the presence of microporosity, which enhanced the surface area of the scaffolds. Moreover, the alkaline phosphatase (ALP) activity of the MG63 cells on micro/ma-MCP was significantly higher than ma-MCP and CPC scaffolds at 7 days, and the MG63 cells with normal phenotype spread well and formed confluent layers across the macroporous walls of the micro/ma-MCP scaffolds. Histological evaluation confirmed that the micro/ma-MCP scaffolds improved the efficiency of new bone regeneration, and exhibited excellent biocompatibility, biodegradability and faster and more effective osteogenesis in vivo.
Journal: Biomaterials - Volume 31, Issue 6, February 2010, Pages 1260–1269