Microporous SPEEK Implants Decorated with Bioactive PG/CS/HA Hydrogels for Improving Osseointegration Potential

Polyether ether ketone (PEEK) is widely used in orthopedics due to its good mechanical properties and biocompatibility; however, its bioactivity and osseointegration ability are poor. In this article, PEEK materials were dual-modified by surface sulfonation treatment and the loading of active hydrogels (phosphorylated gelatin/chitosan/hydroxyapatite) to improve their bioactivity and osseointegration. Initially, a microstimulated sulfonation process was employed to construct an optimized porous structure on the PEEK surface, with a porosity of 54.63% and an average pore size of 3.38 μm, which significantly improved hydrophilicity and promoted the adhesion and growth of osteoblasts. Subsequently, utilizing the adhesive properties of polydopamine (PDA), the phosphorylated gelatin/chitosan/hydroxyapatite composite hydrogel (PG/CS/HA hydrogel) was loaded onto the surface of SPEEK, resulting in the construction of a highly active and strongly osteogenic SPEEK-PG/CS/HA material. The results showed that the dual modification of the porous sulfonated structure and bioactive hydrogel significantly enhanced the hydrophilicity, biocompatibility, mineralization ability, and osseointegration of the PEEK. Specifically, the cell proliferation capacity increased by 32% after 7 days of coculture on MC3T3-E1 cells; the alizarin red staining rate after 14 days of coculture reached 72.49%, representing a 111% improvement; and the expression levels of osteogenic genes ALP, OPN, and RUNX2 increased by 132%, 151%, and 131%, respectively, demonstrating excellent in vitro osteogenic induction potential. The SPEEK-PG/CS/HA material effectively solves the problem of bioinertia in the PEEK material, offering a novel modification strategy for orthopedic implants.