Dimensional-dependent antibacterial behavior on bioactive micro/nano polyetheretherketone (PEEK) arrays

Polyetheretherketone (PEEK) is a biocompatible polymer but the poor bacteria resistance and bioactivity have hampered its wider application to orthopedics. Inspired by the natural antibacterial structure on insect wings, cone/pillar-like micro/nano-arrays are fabricated controllably on PEEK by colloidal lithography and plasma etching and the resulting bacterial resistance and biocompatibility are investigated. The surface-engineered PEEK possesses enhanced antibacterial properties and the underlying mechanism depends on the surface topography and dimensions of the surface structures. With regard to the microarrays, both the early mechanical stretching effect and subsequent dimensional effect contribute to the overall antibacterial effects. On the other hand, the nanoarrays that mimic cicada wings kill bacteria solely by the penetration effect. Enhanced proliferation of osteoblasts is also observed from the modified PEEK rendering it suitable for implant materials. The antibacterial principles concluded from this work provide insights into the design and fabrication of bio-inspired biomaterials with improved bacteria resistance and biocompatibility.