Non-Specific Protein Adsorption on Polyetheretherketones -Challenges for Application as Biomaterial

Abstract

This work deals with the investigation of the non-specific protein adsorption on polyetheretherketones (PEEK). As this polymer has positive characteristics like high comparable mechanical properties to bone and bio-inertness, it is more and more used as implant material in orthopaedics and dentistry. However, non-specific protein adsorption to PEEK has not been investigated in detail and can be a challenge for surface bioconjugation, as one method to enhance bone-PEEK contact. Here, we analysed and compared the influence of different PEEK-surfaces, modified via plasma-and wet-chemical processes. First, the surfaces of the various modified PEEK films were characterized regarding surface properties. In addition, the protein adsorption on differently modified films was quantified at the model of bovine serum albumin via an adapted protein assay. Striking is the comparison of contact angle measurement with the protein adsorption, evidencing higher protein adsorption with increased hydrophobicity of PEEK surfaces. The pure PEEK-film is extremely hydrophobic and shows the highest protein loading. Chemically treated films show a slightly lower contact angle and also a slightly decreased protein adsorption, while the plasma treated films, show a very low contact angle immediately after modification and a very low protein adsorption. However, in another measurement after 14 day of storage a significant increase in protein adsorption and contact angle was recognized. This result clarifies how PEEK surface modification affects non-specific protein adsorption.