A surface-engineered polyetheretherketone biomaterial implant with direct and immunoregulatory antibacterial activity against methicillin-resistant Staphylococcus aureus

Metal ions or nanoparticles are believed to be promising additives in developing antibacterial biomaterials, owing to possessing favorable bactericidal effects against antibiotic-resistant bacteria. However, the immunomodulatory antibacterial activity of metal ions has seldom been reported. Herein, a porous microstructure designed to trap methicillin-resistant Staphylococcus aureus (MRSA) is fabricated on polyetheretherketone biomaterial surface through sulfonation (SPEEK), following which copper (Cu) nanoparticles, which can kill the trapped MRSA, are immobilized on SPEEK surface using a customized magnetron sputtering technique. In vitro antibacterial and immunological experiments indicate that the Cu-incorporated SPEEK can exert a desirable bactericidal effect against MRSA through the combination of "trap killing" and "contact killing" actions; meanwhile, macrophages cultured on the Cu-incorporated SPEEK can be activated and polarized to a pro-inflammatory phenotype along with improved phagocytic ability on the MRSA. Further in vivo implant-associated infection models evidence the superior antibacterial activity of the Cu-incorporated SPEEK. These results demonstrate multimodal antibacterial actions of the Cu-incorporated SPEEK, which is capable of imposing direct antibacterial and indirect immunomodulatory antibacterial effects simultaneously, in order to prevent and cure MRSA infection. It is believed that this study may shed light on developing novel biomaterial implants that combine antibacterial and immunomodulatory functions.