Polyether ether ketone coated with nanohydroxyapatite/graphene oxide composite promotes bioactivity and antibacterial...

Polyether ether ketone (PEEK) is considered an alternative material for manufacturing dental implants. However, PEEK lacks bioactivity and antibacterial action. In a series of experiments designed to enhance the surface properties of PEEK, we present a nanohydroxyapatite (nHA) and graphene oxide (GO) composite as a coating for PEEK-based dental implants to improve biological properties and antibacterial action. PEEK discs were polished, cleaned, and coated with the composite consisting of nHA particles doped with 0.75 wt% graphene oxide by a micro-emulsion technique according to patent US8,206,813. X-ray diffraction, field emission scanning electron microscopy-energy dispersive spectroscopy, and atomic force microscopy were utilized to characterize the composite coating. The wettability of the coated and non-coated samples was assessed by optical contact angle measurement. Antibacterial action of the composite coating was explored against S. aureus and E. coli and cytotoxicity determined utilizing osteoblast-like cells and gingival fibroblasts. The findings showed that the nHA/GO composite coating, approximately 1.3 μm thick, was homogenous with few micro-cracks and adhered to the PEEK surface. The surface roughness was reduced to 21.26 nm and the wettability was improved to 54.6⁰ after coating with the composite coating. Antibacterial activity was moderate, killing 99% of S. aureus and E. coli, with acceptable levels of cytotoxicity to mammalian osteoblast-like cells and gingival fibroblasts.