Effect of the micro/nanostructured topography of polyetheretherketone on the behavior of MC3T3-E1 preosteoblasts

Polyetheretherketone (PEEK) is of interest because of its excellent mechanical properties. However, the bioinert nature of PEEK limits its use in clinical applications. In this study, a series of micro/nanostructures combining nano-, submicron-, and microscale on PEEK were fabricated with 0.5, 1, 4, and 6 min of sulfonation time (S1, S2, S3, and S4). Compared to the flat surface on PEEK, the micro/nanostructure of different sizes all significantly promote cell adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. It is shown that micro/nano-porous structures with smaller size and lower roughness of S1 enabled faster cell propagation. The results of alkaline phosphatase staining, alizarin red staining, and quantitative real-time PCR reveal that the osteogenic activity of MC3T3-E1 cells gradually decreases with the increasement of pore size, indicating that the micro/nanostructured topography of S1 generated substantially increased matrix mineralization and bone-like nodule formation, compared to the 3D network surface. This work provides an effective strategy for designing biomaterials with potential clinical applications.