It is well known that many important pathogens, S. However, antibiotic resistance is an important problem that requires primary clinical attention 22. The properties of the MAO coatings depend on certain experimental parameters such as the substrate, the electrolyte, voltage, current, and the treatment time 19.Īntibiotics could be presented to the implant surface to reduce the risk of postoperative infection by preventing microbial adhesion and proliferation 20, 21. Eventually, porous and rough bioceramic surfaces form on metal surfaces. The short-lived micro-discharges occur locally at weak sites that are susceptible to dielectric breakdown under the high temperatures and pressures associated with the MAO process 17, 18. MAO, which produces bioactive and biocompatible ceramic coatings, involves anodic oxidation in aqueous electrolytes above the dielectric breakdown voltage. MAO that can form porous, thick, relatively rough, and firmly adherent oxide coatings on zirconium surfaces represents a promising electrochemical coating technique 2, 5, 15, 16. Micro-arc oxidation (MAO) enhances bioactivity, biocompatibility, and corrosion resistance 2, 5, 13, 14. In order to overcome this disadvantage, it is vital to enhance the bioactivity and antimicrobial properties via surface treatment. Thus, zirconium has limited medical applications. It is clear that one of the major problems with the implant surfaces is microbial colonization, whereas their bioactivity and biocompatibility are improved 10, 11, 12. Moreover, the microbial property of zirconium may cause postoperative infection 7, 8, 9. However, zirconium cannot directly bond to bone tissue at an early stage after implantation due to its bioinert nature 5, 6. Zirconium can be a potential candidate for surgical implant material due to its promising properties such as low Young’s Modulus (92 GPa) and excellent biocompatibility compared to titanium and its alloys 2, 3, 4. The amount of zirconium that exists in the body is only 1 mg in total on average, and does not have a natural biological role in the human body 1. In vitro microbial adhesions on the chitosan-based MAO surfaces were lower than the MAO surfaces for Staphylococcus aureus and Escherichia coli. In vitro bioactivity was significantly enhanced on the chitosan-based MAO surface with respect to the MAO surface. In vitro bioactivity on both surfaces was investigated via XRD, SEM, and EDX analyses post-immersion in simulated body fluid (SBF) for 14 days. However, the contact angle of the MAO surface was lower than that of the chitosan-based MAO surface. Moreover, both surfaces indicated hydrophobic properties. All elements such as Zr, O, Ca, P, and C were homogenously distributed across both surfaces. The micropores and thermal cracks on the bioceramic MAO surface were sealed using a chitosan coating, where the MAO surface was porous and rough. The existence of chitosan on the MAO-coated Zr surfaces was verified by FTIR. Cubic ZrO 2, metastable Ca 0.15Zr 0.85O 1.85, and Ca 3(PO 4) 2 were detected on the MAO surface by powder-XRD. Subsequently, the MAO-coated zirconium surfaces were covered with an antimicrobial chitosan layer via the dip coating method to develop an antimicrobial, bioactive, and biocompatible composite biopolymer and bioceramic layer for implant applications. Ca-based porous and rough bioceramic surfaces were coated onto zirconium by micro-arc oxidation (MAO).
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