Bioderived amorphous calcium phytate as artificial bone substitute

Abstract

Calcium phosphates have been widely used in clinics as bone substitutes due to their excellent biocompatibility and similar chemical compositions to bone minerals. The best-known commercial products are hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), however, their degradation rates do not match well with the formation of new bone, making them somehow unsatisfactory. A degradation rate between these two would be more suitable for bone regeneration and such materials are consistently sought. In this study, we developed a bioderived amorphous calcium phytate (a-CP). Compared with HA and β-TCP, a-CP showed similar effects on proliferation, better effects on differentiation and mineralization of osteogenic related cells. The degradation rate of a-CP fell between β-TCP and HA: In vivo, β-TCP was found to degrade in 4 weeks, while no sign of degradation was observed for HA groups in 8 weeks; the degradation rate of a-CP appeared to be more appropriate. Consequently, a-CP showed better curative effect than both HA and β-TCP in femoral condyle defects: 51±4% of new bone formation was observed on the site of a-CP, while 34±3% and 40±4% of HA and β-TCP groups, respectively. This article is the first to explore the potential of a-CP as a bone substitute, and the in vitro and in vivo performances indicate it to be a promising candidate for bone defect repairing.