Strong adhesive and drug-loaded hydrogels for enhancing bone–implant interface fixation and anti-infection properties

The bonding strength of the bone–titanium (Ti) implant interface is critical for patients undergoing joint replacement. However, current bone adhesives used in clinic have shortcomings, such as biological inertness, cytotoxicity, and lack of osteogenic ability. In this study, a simple and low-cost hydrogel-based bone adhesive was prepared to improve the osseointegration ability and anti-infection ability of the bone–implant interface. A multifunctional hydrogel was prepared by incorporating nano-hydroxyapatite (HA) on polyethyleneimine (PEI) and polyacrylic acid (PAA) (PEI/PAA–HA). It was shown that PEI/PAA–HA hydrogel exhibited good self-healing and strong adhesive ability. The adhesive strengths of bone–Ti and Ti–Ti were measured as 2.30 ± 0.15 MPa and 1.07 ± 0.07 MPa, respectively. Vancomycin (VAN) was loaded into the PEI/PAA–HA hydrogel (PEI/PAA–HA-VAN) via a simple immersion method. The PEI/PAA-HA-VAN showed excellent antibacterial effect by sustained release of VAN. In addition, the PEI/PAA-HA-VAN hydrogel exhibited excellent cytocompatibility promoting the expression of osteogenic genes and the deposition of mineralized matrix. Collectively, this strong adhesive hydrogel showed great potential in enhancing bone-implant interface fixation.