Osteoclast Response to Bioactive Surface Modification of Hydroxyapatite

The aim of this study was to evaluate the in vitro response of osteoclast-like cells (RAW 264.7 cells) to a bioactive hydroxyapatite (HAP) surface that was modified using the 30% phosphoric ac-id-etching procedure reported in our previous paper (2013). The cells on the bioactive HAP surface were multinucleated and were larger than those on the untreated HAP surface. The cell occupancies were greater on the bioactive HAP surface than on the untreated HAP surface at 7, 14, 21, and 28 days of differentiation; in particular, the values at 21 and 28 days were significantly larger (P < 0.05 and P < 0.01, respectively). These findings show that the bioactive HAP surface may enhance the adhesion and differentiation of RAW 264.7 cells as well as osteoblast-like cells, indicating its potential as a superior surface for bone tissue engineering.