Investigation on performance of hybrid coating of hydroxyapatite and reduced graphene oxide on polyether ether ketone for orthopaedic application

The replacement of metal implants with more biocompatible material are increasing day-by-day in the medical industry. Biopolymers and bioactive ceramics are currently being evaluated as possible replacement materials due to their lower stress shielding impact than metal. As the use of implants grows, so does the prevalence of implant-associated infection, a significant complication, particularly in orthopaedic implants. As a result, orthopaedic polymer implants have been subjected to a myriad of surface changes to increase their biofunctionality inside the host site. In this study, hydroxyapatite (HAp) and reduced graphene oxide (rGO) were used as coating material on the polyetheretherketone (PEEK) sample. The impact of several coating combinations and patterns was explored. In combination I, HAp is coated at the bottom and rGO is coated at top (HAp/rGo). In combination II, rGO is coated at the bottom and HAp is at the top (rGo/HAp). The combination III has a mixed coating of HAp and rGo (HAp + rGO). To analyse the elemental composition and morphology of the coatings, scanning electron microscopy, X-ray diffraction computed tomography and 3D contour profiles were used. The results revealed that HAp dominates the combination, with a minor contribution from rGO. However, rGO acts as an interstitial bonding agent between PEEK and HAp, resulting in increased bond strength, with the HAp + rGO combination achieving the greatest bond strength of 35.67 MPa.