Cu-doped HA coating with osteogenic and antimicrobial properties on porous tantalum

Porous tantalum (Ta) implants have exhibited exceptional clinical performance in bone defect reconstruction for several decades. However, the poor osseointegration and antibacterial capability of unmodified Ta implants restrict their broader clinical application. This study presents an innovative composite material fabricated via hydrothermal synthesis: Cu-doped hydroxyapatite (HA) coatings applied to Ta substrates (designated as HA-xCu, where x = 1, 3, or 5 wt%). In vitro results indicated that the composites had good biocompatibility, bone integration, and antibacterial properties. Cu incorporation promoted the release of Cu²⁺ and Ca²⁺, which contributed to bactericidal effects by inducing the production of reactive oxygen species (ROS), increasing intracellular malondialdehyde (MDA) levels, and enhancing catalase (CAT) activity. Simultaneously, the composites upregulated the expression of osteogenesis-related genes, as confirmed by increased alkaline phosphatase (ALP) activity and positive Alizarin Red Staining (ARS) results. RNA sequencing and western blot analysis revealed that HA-5Cu activated the MAPK signaling pathway to promote osteogenesis. In vivo experiments further demonstrated that HA-5Cu accelerated infection healing and promoted bone regeneration, thereby exhibiting synergistic antibacterial and osteogenic effects. These findings underscore the promising potential of Ta-based implants to meet antimicrobial and osseointegration requirements in clinical orthopedic applications.