A bioactive Cu-grafted gel coating with micro–nano structures for simultaneous enhancement of bone regeneration and infection resistance

Prosthetic joint infection (PJI) remains a significant challenge in clinical applications. It not only impedes the recovery of bone tissue at the site of bone defect but also leads to multiple debridements, long-lasting antibiotic treatment and even secondary replacement. Titanium alloy Ti6Al4V (TC4) is widely used in orthopedic implants due to its excellent mechanical properties and biocompatibility; however, it lacks inherent antibacterial and osteoinductive functions. In this study, a composite coating based on polyvinyl alcohol (PVA) with tissue repair and antibacterial properties was applied on the surface of TC4. A PVA gel coating functionalized with terpyridine and catechol groups (PVA-TP-CA) was synthesized and subsequently complexed with copper (Cu) ions. The differential binding affinities of TP and CA groups to Cu enabled a sustained and controlled release of metal ions. Furthermore, a micro-nano surface structure was fabricated on TC4 using femtosecond laser technology to achieve a micro-nano structure interface and enhanced bonding strength. Biological evaluations demonstrated that the modified surface significantly improved the antibacterial, angiogenic, and osteogenic properties of TC4. These findings indicate that this multifunctional composite coating holds great promise for surface modification of orthopedic implants, offering an effective strategy for preventing PJI while promoting bone regeneration.