Exploring hydroxyapatite/graphene oxide/zinc oxide composite powders for the preparation of bioactive-antibacterial coatings by HVOF

Infection is one of the most common complications in orthopedics and causes significant post-operative morbidity and mortality. Among different strategies to fight infections, incorporation of graphene-based compounds on HAp-based coatings present several advantages from a biological point of view, i.e. non-toxicity, cell proliferation. In this research, the preparation of hydroxyapatite/graphene oxide/zinc oxide (HAp/GO/ZnO) powders is presented. The HAp/GO/ZnO mixture was, in turn, used as feedstock material to fabricate HAp-based high-velocity oxygen fuel spray (HVOF) coatings on titanium substrates. It was found that particle size and GO/ZnO and ZnO content in the mixtures play a key role in the coating formation. On the other hand, the antibacterial activity of the synthesized (GO/Zn) powder, (HAp/GO/ZnO) powder mixtures, and HVOF-sprayed coatings was evaluated against Escherichia coli and Staphylococcus aureus strains. The obtained antibacterial activity data were statistically analyzed by employing the one-way ANOVA method followed by a Duncan's post hoc test. The results showed that HAp/GO/ZnO powder mixtures display antibacterial activity against both bacterial strains. However, despite the reduction in antibacterial activity observed in the coating compared to that in the starting powders, the results showed the feasibility of using this type of system in the manufacturing of HVOF coatings with bioactive and antibacterial properties aiming for a better performance under in-vivo conditions.