Zwitterionic polymer functionalized polyetheretherketone biointerfaces enhance osseointegration and antibacterial through in situ inducing biomineralization

Polyetheretherketone (PEEK) is increasingly recognized as a promising biomaterial for orthopedic implants due to its mechanical properties that are very similar to those of human bones. However, its inherent bioinertness still poses a challenge to effective osseointegration, and surface modification of PEEK implants often faces limitations such as multi-step complexity. In this study, we innovatively developed a dopamine-triggered one-step polymerization of 3-[(3-acrylamidopropyl)dimethylammonio] propanoate (PCBAA), which in situ induced biomineralization and constructed a functional PEEK biointerfaces, directly and effectively enhancing osseointegration and antibacterial effects. The successful immobilization of PCBAA on the surface of PEEK significantly enhanced osteogenic differentiation of bone mesenchymal stem cells, as evidenced by the significant improvement in alkaline phosphatase activity and mineral deposition. Moreover, the functional biointerfaces exhibited substantialantibacterial efficacy in vitro. Micro-computed tomography (micro-CT) and histological evaluation of rat tibia implantation showed that compared to uncoated screws, the PCBAA-functionalized PEEK screws significantly enhanced new bone formation and possessed superior pull-out strength. The findings of this study suggest that the one-step polymerization of PCBAA coatings on PEEK substrates is facile and can efficiently overcome the limitations of current surface modification. The resultant PCBAA-coated PEEK biointerfaces have shown great promise in promoting osseointegration and mitigating postoperative infections for clinical outcomes of PEEKbased orthopedic implants.