Tailoring microenvironment responsive Fe/Cu micro-galvanic couples on polyetheretherketone for selective antibacteria and osteogenesis

Polyetheretherketone (PEEK) has become an ideal bone implant material owing to its good mechanical properties and X-ray permeability, however, bacterial infection and aseptic loosening often lead to implant failure. Therefore, it is urgent to enhance its osteogenic and antibacterial capabilities, but how to selectively kill bacteria and improve osteogenesis remains an intractable challenge. Here, we designed a microenvironment-responsive Fe/Cu micro-galvanic couple modified layer, which was in situ fabricated on PEEK via plasma techniques. The electron transfer effect of Fe/Cu micro-galvanic couples induced the production of hydroxyl radical and superoxide anion, and this process could be enhanced in the acid bacterial infection microenvironment. Thus, the as-prepared modified PEEK showed good broad-spectrum antibacterial properties with bactericidal efficiency of 99.9 % against both S. aureus and E. coli in vitro, and 98.6 % against S. aureus in vivo. More importantly, in the normal physiological environment, the Fe/Cu nano heterostructure modified layer could promote the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells. This innovative strategy gives a new slight for endowing PEEK implants with selective antibacterial and osteogenic abilities, which has great potential in the clinic.