Enhancing bone regeneration with a novel bioactive glass-functionalized polyetheretherketone scaffold by regulating the immune microenvironment

Polyetheretherketone (PEEK) has become a promising material for bone engineering due to its excellent mechanical properties, radiolucency and chemical resistance. However, its inherent bioinertness and lack of osteogenic activity induce a foreign body reaction and fibrous encapsulation, which limits its effectiveness in promoting bone regeneration. Herein, we develop a novel bioactive glass–functionalized PEEK scaffold (ADSP) to accelerate bone regeneration by immunoregulation. Strontium-doped bioactive glass nanoparticles loaded with alendronate (A-SrBG) were coated on the sulfonated PEEK scaffold by the strong adhesion ability of polydopamine. The released bioactive ions from the scaffold can improve the biocompatibilities and osteogenic activity of PEEK. In vitro results showed the ADSP scaffold promoted polarization of the M2 macrophages via the NF-κB pathway to enhance the osteogenic differentiation of rat bone mesenchymal stem cells (rBMSCs). Further, in vivo rat skull drilling model assessment revealed efficient polarization of M2 macrophage and desirable new bone formation. Thus, ADSP scaffold exerted osteoimmunomodulation effect to promote bone regeneration.