Additively-manufactured poly-ether-ether-ketone (PEEK) lattice scaffolds with uniform microporous architectures for enhanced cellular response and soft tissue adhesion

Additively-manufactured PEEK orthopedic implants have recently gained extensive attention due to their prominent characteristics such as good biocompatibility, low radiographic artifacts and similar elastic modulus to native bones. However, the inherent drawback associated with PEEK implants was their biologically inert surface which caused unsatisfactory cellular response and poor adhesion between the implants and surrounding soft tissues. Here we developed a sulfonation-treatment strategy to create microporous architectures onto the filaments of the additively-manufactured PEEK lattice scaffolds. The sulfonation time in the range of 30–45 s was found to facilitate the formation of uniform microscale pores throughout the printed PEEK lattice scaffolds and simultaneously have slight effect on their composition and mechanical properties. Biological results showed that the presence of microscale pores on the additively-manufactured PEEK lattice scaffolds significantly improved the spreading, proliferation and calcium deposition of bone-specific cells in comparison with the untreated PEEK lattice scaffolds. In vivo experiments demonstrated that the sulfonation-treated micropores facilitated the adhesion of newly-regenerated soft tissues to form tight implant-tissue bonding interfaces. The presented method provides a promising approach to improve the surface bioactivity of additively-manufactured PEEK lattice scaffolds for enhanced cellular response and soft tissue adhesion.