Nanoarchitectonics of PEEK Scaffold with VitaFlux Adaptability: Immune Microenvironment Remodeling and Empowered Activation of Latent TGF-β1 Expression

Once bone is damaged, a rapid surge of reactive oxygen species (ROS) and anaerobic glycolysis will create an oxidative stress and acidic microenvironment, thus inhibiting osteogenic factor expression and disrupting bone regeneration. To address this, we innovatively developed an alkaline hydrogel-coated poly(ether ether ketone) (PEEK) porous scaffold with VitaFlux functionality in this study. This decorated PEEK scaffold distinct from those hydrogel-perfused scaffolds with obstructed pores still kept its initial 3D-printed pore structure to allow the ingrowth of bone tissues. The results showed that the modified scaffold could not only exhibit significant efficacy in lowering oxidative stress, neutralizing acidic microenvironment, and activating TGF-β1 expression in serum through its inherent alkalinity but also recruit stem cells to the bone defect site and upregulate osteogenic factor expression via the TGF-β1/Smad signaling pathway. This study proved the obvious advantage of the modified scaffold in enhancing bone regeneration by the synergy of immune microenvironment remodeling and osteogenic factor expression enhancement, thus providing a facile method to modify bone scaffold which can facilitate a desirable bone repair process through self-activating the transfer of growth factors between the material and tissues.