A preliminary study on surface bioactivation of polyaryletherketone by UV-grafting with PolyNaSS: influence on osteogenic and antibacterial activities

Polyaryletherketone (PAEK) has good biocompatibility and mechanical properties and thus may have great potential in the fields of reparative medicine and bone intervention. In this study, the key representative PAEKs, polyetheretherketone (PEEK) and polyetherketoneketone (PEKK), were modified by UV grafting with sodium polystyrene sulfonate (polyNaSS) to improve their biocompatibility. Toluidine blue staining and Fourier transform infrared spectroscopic analyses showed that sulfonic acid groups were successfully introduced into PAEK, and the hydrophilicity and protein adsorption capacity of the materials were enhanced in a concentration-dependent manner. The effects of the grafted polyNaSS on osteoinduction and antibacterial properties of PAEK were analyzed in detail. We found that polyNaSS enhanced the viability, alkaline phosphatase activity, calcium mineral deposition, and levels of expression of osteoblast-related genes and proteins of adherent human umbilical cord Wharton's jelly-derived mesenchymal stem cells. In addition, when Escherichia coli, Staphylococcus aureus and Porphyromonas gingivalis were incubated with the materials, bacterial colony counting revealed that grafting of polyNaSS onto PAEK led to more potent inhibition of bacterial adhesion, and polyNaSS-grafted PEKK had stronger antibacterial performance than did polyNaSS-grafted PEEK fabricated under the same grafting conditions. These data show that polyNaSS-grafted PAEK, and particularly polyNaSS-grafted PEKK, may be useful as orthopedic and dental implant materials.