Electrophoretic deposition of graphene oxide reinforced hydroxyapatite on the tantalum substrate for bone implant applications: In vitro corrosion and bio-tribological behavior

Abstract

Tantalum (Ta) is used in dental implantology due to its high biocompatibility and potential clinical applications. Ta has low bone regeneration and low abrasion resistance , which can lead to inflammatory reactions in biological environments. In the present study, the graphene oxide/hydroxyapatite (GO/HA) composite on the Ta substrate was coated using the electrophoretic deposition technique. The deposition process was conducted at a constant voltage of 30 V at two deposition times of 5 and 10 min. Confocal Raman spectroscopy , Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) confirmed GO in the GO/HA composite coating layer. The roughness of samples increased from 35 ± 3 nm for the GO/HA-coated Ta (at 10 min) to 120 ± 4 nm for the uncoated Ta. After coating Ta with the GO/HA at deposition time of 10 min, nanoindentation curve shifted to the left and maximum depth decreased due to an 18-fold increase in the hardness of coated sample in comparison to the uncoated Ta. The GO/HA composite coating improved the bio-tribological behavior, the resistance to plastic deformation , and fracture toughness of Ta substrate. The stiffness of GO/HA-coated Ta (at 10 min) was 8-fold higher than that of the uncoated Ta. Additionally, the friction coefficient of GO/HA-coated Ta (0.3) was lower than the uncoated Ta (0.43). The GO/HA-coated Ta (at 10 min) showed significantly higher corrosion current density (18.6 ± 1.2 vs 4.97 ± 0.23 μA/cm 2 ) compared to the uncoated Ta. The results of antibacterial activity test indicated that the presence of GO in the GO/HA coating decreased the viability of Escherichia coli and Staphylococcus aureus cells on the surface of Ta. Due to higher surface roughness and wettability of the GO/HA-coated Ta compared to the uncoated Ta, the proliferation and viability of MG-63 cells on the surface of GO/HA-coated Ta significantly increased. Our findings demonstrated that the GO/HA composite coating can enhance the lifetime of Ta based dental and orthopedic implants. • The GO/ HA composite coating was successfully prepared and deposited on the Ta surface during EPD process. • The GO/ HA-coated Ta showed the high corrosion protection and antibacterial activity compare to the uncoated Ta. • The GO/ HA coating improved the bio-tribological behavior, resistance to plastic deformation, and fracture toughness of Ta. • The GO/HA caused an increase in the hydrophilicity and roughness, which enhanced the proliferation of cells on Ta surface. • The GO/HA composite coating on the Ta surface could be a promising candidate for dental and orthopedic implants.