Mixed Modification of the Surface Microstructure and Chemical State of Polyetheretherketone to Improve Its Antimicrobial Activity, Hydrophilicity, Cell Adhesion, and Bone Integration

Polyetheretherketone (PEEK) is becoming an attractive surgical implant material in the biomedical field. However, its hydrophobicity and biological inertia have seriously hindered its development in the field of biomaterials and application in clinic. In this work, a mixed modification approach of the surface structure and chemical state was proposed to improve hydrophilicity and bioactivity of PEEK and meanwhile endowed it with antimicrobial properties. First, the effect of mixed acids of nitric acid and concentrated sulfuric acid with different volume ratios on the surface morphology of PEEK was quantitatively investigated, so as to obtain an optimal mixed acid of nitric acid and concentrated sulfuric acid with a volume ratio that could create a multilevel porous structure. Based on this, chemical grafting of ethylenediamine was conducted to achieve amination on the surface of the PEEK. The results showed that such double modification of the surface structure and chemical state could endow PEEK not only with antimicrobial activity but also with good hydrophilicity, cell compatibility, and bioactivity, which were beneficial to improve the bone integration ability of PEEK greatly.