Tightly anchoring bone‐like coating on the surface of titanium implants with complex three‐dimensional geometry through radical polymerization

Abstract Biological fixation of a Ti implant demonstrates significant advantages over conventional physical fixation. Modifying the surface of Ti implants with hydroxyapatite (HAp) coating has proven to be a promising strategy to enhance their bone integration capability in vivo. The currently reported strategies are confronted with the following problems: (i) low interfacial bonding strength and poor structural stability under mechanical force; (ii) being incapable of encapsulating Ti implants with complex 3D geometry; (iii) complicated processing procedures and high processing costs. Here, we fabricated a bone‐like polyacrylamide/poly(vinyl alcohol)/HAp (PAAm/PVA/HAp) coating on the surface of Ti implants with complex 3D geometry through thermal induced in situ radical polymerization of pre‐adhered vicious acrylamide/PVA/HAp (AAm/PVA/HAp) emulsion. Covalent interaction between the Ti matrix and the coating was constructed through incorporating vinyl groups on the surface of Ti matrix using 3‐(trimethoxysilyl)propyl methacrylate (TMSPMA). The as‐prepared coating demonstrated a record high shear bonding strength of 144.5 MPa and 75.50 MPa in dry and moist states, respectively. In addition, its interfacial toughness reached to 1.27 kJ/m², while its maximum motion under shear mechanical force was only 0.64 mm (moist state). Anti‐fatigue tests (approximate 100% toughness retention rate at displacement of 0.1 mm) and degradation experiment exhibited the long‐term mechanical/structural stability of the coating in a in vivo environment. BMSCs co‐culture assay demonstrated the superior cytocompatibility and osteogenic property of the coating. In sum, this work provided a simple and cost‐effective strategy to construct homogeneous and tightly anchored HAp coating on the surface of Ti implants with complex 3D geometry. Highlights Homogeneous coating on Ti surface with bone‐like composition and structure. Being capable of encapsulating Ti implants with complex 3D geometry. Record high interfacial bonding strength/toughness. long‐term structural/mechanical stability in a moist environment. Superior biocompatibility and osteogenic property.