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Surface modification of titanium with hydroxyapatite–heparin–BMP‐2 enhances the efficacy of bone formation and osseointegration in vitro and in vivo

Surface‐modified titanium (Ti) samples with hydroxyapatite (HAp) and heparin (Hep)–bone morphogenetic protein‐2 (BMP‐2) complex (Ti/HAp/Hep/BMP‐2) were prepared, and their efficacies on the enhancements of bone formation and osseointegration in vitro and in vivo were examined as compared to Ti/HAp and Ti/Hep/BMP‐2. The modified surfaces were characterized by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle goniometry. In vitro studies revealed that MG‐63 human osteosarcoma cell lines grown on Ti/HAp/Hep/BMP‐2 increased the amounts of alkaline phosphatase (ALP) activity, calcium deposition and the levels of OCN mRNA gene expression as compared to those grown on Ti/HAp, Ti/Hep/BMP‐2 or pristine Ti. Moreover, Ti/HAp/Hep/BMP‐2 exhibited higher bone volume (BV), bone volume/tissue volume (BV/TV), removal torque value and bone–implant contact (BIC) than Ti/HAp, Ti/Hep/BMP‐2 or pristine Ti in vivo. Histological evaluations showed that many desirable features of bone remodelling existed at the interface between Ti/HAp/Hep/BMP‐2 and the host bone. Consequently, Ti/HAp/Hep/BMP‐2 may have potential for clinical use as dental or orthopaedic implants. Copyright © 2014 John Wiley & Sons, Ltd.