Osteopontin functionalization of hydroxyapatite nanoparticles in a PDLLA matrix promotes bone formation.

We studied the osteoconductive tissue response of hydroxyapatite (HA) nanoparticles functionalized with osteopontin (OPN) in a matrix of poly-D,L-lactic-acid (PDLLA). In a canine endosseus 0.75-mm gap implant model, we tested the osteointegrative impact of the OPN functionalized composite as an implant coating, and a non-functionalized composite was used as reference control. During the four weeks of observation, the OPN functionalized composite coating significantly increased the formation of new bone in the porosities of the implant, but no differences were observed in the gap. The study provides evidence of its potential use either alone or in combination with other osteoconductive compounds.