Cicada-inspired fluoridated hydroxyapatite nanostructured surfaces synthesized by electrochemical additive manufacturing

Recently, the cicada-inspired nanostructured surfaces have attracted much interest because they possess remarkable bactericidal ability. However, Gram-positive bacteria are less damageable by the nanopillar structure of a cicada wing surface compared to Gram-negative species. To overcome this shortcoming, fluoridated hydroxyapatite (FHA) is employed owing to its effective antibacterial ability against both Gram-negative and Gram-positive bacteria. Here, we design a novel potential antibacterial surface by combining the cicada wing like nanopillar structure and the FHA together to potentially exert the advantages of physical and chemical antibacterial strategies simultaneously for battling the antibiotic-resistant pathogenic bacteria more effectively. Cicada-inspired FHA nanostructured surfaces have been successfully fabricated on acid-etched titanium (AETi) plates using an electrochemical additive manufacturing (ECAM) method for the first time. The as-prepared FHA nanopillar array consists of close-packed individual nanopillars with diameters, heights, and aspect ratios of-65-95 nm,-380-510 nm, and -4.5-7.5, respectively. The chemical composition of the FHA nanopillar array is similar to that of the Ca-10(PO4)(6)(OH)F. Individual FHA nanopillars possess high crystallinity, long-range regularity, and flaw-free lattices with the [0001] orientation. Our new, cost-effective, and time-saving method for fabricating cicada-inspired FHA nanostructured surfaces could potentially endow orthopedic and dental implants with enhanced antibacterial performance for biomedical applications. (C) 2020 The Author(s). Published by Elsevier Ltd.