Designing a heterostructure of graphite-like layer/TaOx on polyetheretherketone for selective antibacteria and osteogenesis.

Implant-associated infection remains a critical challenge for orthopedic implants, particularly for bioinert polyetheretherketone (PEEK), which also requires improved osteogenic support. Here, we developed a heterostructured surface on PEEK by coupling a graphite-like layer with a defect-rich TaOx nanoarray. The graphite-like layer promoted uniform TaOx nanoarray formation and may facilitate interfacial electronic coupling, while the TaOx nanoarray showed polarity-dependent and interface-limited charge-transport behavior in model electrical tests. Upon bacterial contact, the heterostructure produced a bacteria-associated 3,3',5,5'-tetramethylbenzidine (TMB) oxidative response and markedly decreased bacterial ATP levels, leading to broad-spectrum antibacterial performance. Thermal annealing attenuated defect-associated TaOx states and weakened antibacterial activity, supporting the involvement of defect-related interfacial states in the antibacterial process. Meanwhile, Ta/H-PEEK supported osteoblast proliferation and osteogenic differentiation in vitro and promoted peri-implant bone formation in vivo. The surface also reduced early bacterial burden in a rat infection model. Collectively, this work demonstrates a heterostructure-based PEEK surface strategy to integrate antibacterial activity with osteogenic compatibility.