Enhanced Antibacterial Ability and Bioactivity ofPolyetherketoneketone Modified with LL-37

Polyetherketoneketone (PEKK) is considered to be a potential substitute material for metal bone implants because ofits advantageous biocompatibility, chemical stability, and mechanical properties, but clinical application has been severely restricteddue to PEKK's lack of antibacterial ability and biological activity. In this study, LL-37, a natural human antimicrobial peptide, wassuccessfully modified on the PEKK surface with polydopamine as the intermediate layer and released continuously for more than 6days. The results of the MTT assay, colony counts, and Live/Dead staining demonstrated that compared to unmodified PEKK, theLL-37-modified PEKK significantly inhibited the adhesion, vitality, and bacterial biofilm growth ofStaphylococcus aureusandEscherichia coliin a concentration-dependent way. Furthermore, the LL-37-modified PEKK enhanced biocompatibility (cell adhesionand viability) and promoted osteogenic differentiation of human umbilical cord Wharton's jelly-derived mesenchymal stem cells.Our data suggested that LL-37-modified PEKK might be a promising material for use in orthopedic implants.