Silk Fibroin-Modified Metal Organic Framework Acid-Controlled Release Nanocarrier for Polyetheretherketone to Combat Implant-Associated Infections and Promote Angiogenesis.

Polyetheretherketone (PEEK) has been regarded as a prospective alternative orthopedic implant, because of its elastic modulus approximately equal to human cortical bone. However, the poor antibacterial and angiogenic properties of bioinert PEEK have become a limitation to its clinical application. Therefore, a biomimetic metal organic framework acid-controlled release nanocarrier consisting of Zeolitic Imidazolate Framework-8 (ZIF-8) nanoparticles loaded with gentamicin and modified with silk fibroin nanospheres for PEEK implants is prepared. In this study, acidity-responsive PEEK implant can efficiently capture bacteria and eradicate bacterial biofilms, achieving antibacterial rates up to 99.9% against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, acidity-responsive PEEK implant is expected to promote angiogenesis by assisting proliferation and migration of endothelial cells, thereby accelerating peri-implant tissue regeneration. By constructing subcutaneous infection models, it is further indicated that acidity-responsive implant can resist bacterial proliferation and facilitate peri-implant angiogenesis. In summary, this study provided an effective approach for the improvement of orthopedic implants that realized antibacterial and angiogenic effects, offering a potential solution for preventing infection and promoting angiogenesis during the early phase after implantation.