Growth factors enhanced angiogenesis and osteogenesis on polydopamine coated titanium surface for bone regeneration

Angiogenesis and osteogenesis have been considered as inseparable and critical processes for bone formation and fracture healing. One promising strategy to improve the capability of angiogenesis and osteogenesis on a titanium (Ti) surface involves the fabrication of stable multifunctional release interfaces. This study developed a combined sequential bio-interfacial release system with basic fibroblast growth factor (bFGF) and bone morphogenetic protein 2 (BMP-2) using a polydopamine (PDA) coating on the Ti surface to enhance angiogenesis and osteogenesis. Their surfaces were characterized and their biological properties were evaluated to provide sufficient supporting evidence for successfully fabricating the combined release system. The novel bio-interface demonstrated a significant improvement in surface hydrophilicity; highly effective growth factor adsorption; and moderate, sustained release on the surface of modified Ti substrates. Furthermore, this system surpassingly promoted the initial proliferation, migration and late angiogenic and osteogenic differentiation of HUVECs and MC3T3-E1 in vitro while also augmenting the osseointegration between the implant surface and the surrounding host tissues in vivo. All these results suggest that the fabrication of this novel bio-interface is a practical modification strategy for Ti implants to stimulate angiogenesis and osteogenesis and further optimize its clinical performance. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).