Composition-Tailoring of ZnO-Hydroxyapatite Nanocomposite as Bioactive and Antibacterial Coating

Overcoming postimplantation infections is considered as a major challenge in medicine, where continuous efforts have been invested in developing bactericidal functional coatings. The synergic combination of hydroxyapatite (HAp) and ZnO holds beneficial properties, such as excellent bioactivity that is reinforced with its antibacterial nature. Here, highly phase tunable pure ZnO-HAp nanocomposite coatings were fabricated via electrophoretic deposition. HAp and ZnO nanoparticles were synthesized separately, dispersed simultaneously, and coelectrophoretically deposited onto a titanium substrate. By manipulating the deposition potentials, a single-stage graded-coating of ZnO-HAp was successfully obtained. In addition, by controlling the composition of the nanomaterials in the dispersions, we managed to precisely tailor composite coatings with a dictated phase ratio between ZnO and HAp. In vitro studies, bioactivity, cytotoxicity, and antibacterial tests, showed excellent performance by enhancing the mineralization of the coating and improving cells proliferation while successfully eradicating E. coli bacteria.