Mussel-Inspired Organic-Inorganic Implant Coating Based on a Layer-by-Layer Method for Anti-infection and Osteogenesis

Lack of antibacterial properties and poor bioactivity of implants' surfaces will increase the risk of implant-associated infections and poor osseointegration, subsequently leading to implant failure. In the present study, an organic-inorganic coating with anti-infection and osteogenesis properties was constructed on the titanium (Ti) implants to enhance the osseointegration. Inspired by the mussel, tannic acid (TA) with abundant catechol groups was chosen as a bonding medium to combine inorganic hydroxyapatite nanoparticles (nHA) with organic polyethylene glycol (PEG) via Layer-by-Layer (LbL) assembly methods. The prepared organic-inorganic coating on the implant (Ti-HP) could effectively prevent the adherence of protein and bacteria including S. aureus and E. coli through highly hydrophilic PEG, and the nHA ingredient endowed the coating with sufficient osteogenic ability to accelerate osteoblast differentiation of rat bone marrow stromal cells (BMSCs). Furthermore, the new bone formation around Ti-HP in vivo was significantly promoted compared with the pure Ti. The study provides a convenient and flexible way based on a polyphenol-assisted LbL method to form an organic-inorganic implant coating with multiple functions, demonstrating its potential for clinical applications in surface engineering of bone repair.