Surface immobilization of MEPE peptide onto HA/β‐TCP ceramic particles enhances bone regeneration and remodeling

Calcium phosphate ceramics have been widely used as scaffolds for bone regeneration. Here, to improve the osteogenic potential of hydroxyapatite/β‐tricalcium phosphate (HA/β‐TCP) and to apply the bioactive peptide in situ , matrix extracellular phosphoglycoprotein (MEPE) peptide, which has been shown to stimulate osteoblast differentiation, was covalently and directionally immobilized on HA/β‐TCP particles. The free‐hydroxyl groups on the surface of the HA/β‐TCP particles were sequentially conjugated with APTES, PEG‐(SS) 2 , and the synthetic MEPE peptide. Using FTIR and XPS, immobilization of the MEPE peptide on the HA/β‐TCP was confirmed. Implantation of the MEPE peptide‐immobilized HA/β‐TCP into calvarial defect and subsequent analyses using a micro CT and histology showed significant bone regeneration and increased bone area (9.89‐fold) as compared to that of unmodified HA/β‐TCP. Moreover, tartrate‐resistant acid phosphatase‐positive osteoclasts were observed in regenerated bone by the MEPE peptide‐immobilized HA/β‐TCP, indicating that the bones newly formed by the MEPE peptide‐immobilized HA/β‐TCP are actively remodeled by osteoclasts. Therefore, our data demonstrate that MEPE peptide immobilization onto the HA/β‐TCP surface stimulates bone regeneration associated with physiological bone remodeling. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.