Bactericidal silver-doped DLC coatings obtained by pulsed filtered cathodic arc co-deposition

• Published in: Surface & coatings technology 2021-04, Vol.411, p.126977, Article 126977
• Main Authors: Orrit-Prat, Jordi, Bonet, Raül, Rupérez, Elisa, Punset, Miquel, Ortiz-Hernández, Mónica, Guillem-Marti, Jordi, Lousa, Arturo, Cano, David, Díaz, Cristina, García Fuentes, Gonzalo, Caro, Jaume
• Format: Article
• Language: English
• Subjects: Adhesion tests; Arc deposition; Bactericidal activity; Biocompatibility; Biomedical materials; Cathodic coating (process); Chemical composition; Codeposition; Corrosion resistance; Corrosion tests; Diamond-like carbon; Diamond-like carbon films; Electrode polarization; Filtered cathodic arc; Free energy; Magnetron sputtering; Materials engineering; Mechanical properties; Morphology; Nanoindentation; P. aeruginosa; Protective coatings; Reagents; S. aureus; Silver; Silver doping; Substrates; Toxicity; Wettability; X ray photoelectron spectroscopy
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2021.126977

Diamond-like carbon (DLC) coatings have been extensively studied over the last two decades in the field of materials engineering. The addition of effective bactericidal agents like silver suggests the potential application of silver-doped DLC coatings in the biomedical sector. In this paper, DLC coatings containing about 2 at. % Ag were grown on CoCrMo substrates by pulsed filtered cathodic arc co-deposition using pure graphite and silver targets. Morphology, structure and chemical composition of the coatings were characterized by SEM, XPS, XRD, Raman and HRTEM. Wettability and surface free energy were also measured. Mechanical properties were analyzed by means of nanoindentation and Rockwell-C adhesion tests. Corrosion resistance of coated and uncoated samples was determined by potentio-dynamic polarization tests in Hank's solution. Cytotoxicity and antibacterial activity against S. aureus and P. aeruginosa were also studied. For comparative purposes, nitrogen-doped DLC coatings obtained by RF magnetron sputtering were also prepared and characterized. Well-adhered and corrosion resistant Ag-DLC nanostructured coatings of up to 1.5 μm thick and 21 GPa in hardness were obtained. The doping concentration of silver studied in this work seems to be optimal for the preparation of non-cytotoxic coatings with a significant bactericidal activity. •Ag-doped DLC coatings were prepared by pulsed filtered cathodic arc co-deposition.•The coatings decrease the surface free energy and increases the hydrophobicity.•Non-cytotoxic, hard, well-adhered and corrosion resistant coatings were obtained.•The coatings exhibit bactericidal activity against S. aureus and P. aeruginosa.