Osteoconductive, Osteogenic, and Antipathogenic Plasma Electrolytic Oxidation Coatings on Titanium Implants with BMP-2

Wereport a one-pot plasma electrolytic oxidation (PEO) strategyfor forming a multi-element oxide layer on the titanium surface usingcomplex electrolytes containing Na2HPO4, Ca(OH)(2), (NH2)(2)CO, Na2SiO3, CuSO4, and KOH compounds. For even better bone implantingrowth, PEO coatings were additionally loaded with bone morphogeneticprotein-2 (BMP-2). The samples were tested in vivo in a mouse craniotomy model. Tests for bactericidal and fungicidalactivity were carried out using clinically isolated multi-drug-resistant Escherichia coli (E. coli) K261, E. coli U20, methicillin-resistant Staphylococcus aureus (S. aureus) CSA154 bacterial strains, and Neurospora crassa (N. crassa) and Candidaalbicans (C. albicans) D2528/20 fungi. The PEO-Cu coating effectively inactivated bothGram-positive and Gram-negative bacteria at low concentrations ofCu(2+) ions: minimal bactericidal concentration for E. coli and N. crassa (99.9999%) and minimal inhibitory concentration (99.0%) for S. aureus were 5 ppm. For all studied bacterial andfungal strains, PEO-Cu coating completely prevented the formationof bacterial and fungal biofilms. PEO and PEO-Cu coatings demonstratedbone remodeling and moderate osteoconductivity in vivo, while BMP-2 significantly enhanced osteoconduction and osteogenesis.The obtained results are encouraging and indicate that Ti-based materialswith PEO coatings loaded with BMP-2 can be widely used in customizedmedicine as implants for orthopedics and cranio-maxillofacial surgery.