Antibacterial coatings on magnesium formed via plasma electrolytic oxidation in CuO suspension

Abstract

Biodegradable materials, especially Magnesium (Mg) and its alloys, are preferred for bone implants due to their compatibility with host tissue and biomechanical support. However, their rapid corrosion and vulnerability to structural failure, compounded by infections from antibiotic-resistant bacteria, pose significant challenges. Addressing these issues, we developed silicate-based composite coatings with varying CuO concentrations (1, 5, and 7 wt%) on Mg using plasma electrolytic oxidation (PEO). This study evaluated the coatings' surface characteristics, degradation behavior, and optimum composition. Our analyses, including XPS and EDX, confirmed the presence and influence of CuO on the coatings. We observed enhanced hydroxyapatite crystallization in CuO-doped coatings, which is critical for implant biocompatibility. These coatings also showed improved corrosion resistance and controlled ion release, likely due to silicate composition and CuO's sealing effects. Antimicrobial assays revealed that CuO concentration influenced bacterial and fungal adhesion, varying with microorganism type. Our findings demonstrate that incorporating inert copper particles into PEO coatings alters their chemical and elemental properties, enhancing bioactivity, corrosion resistance, and antimicrobial efficacy. These multifaceted improvements position our CuO-doped silicate coatings as a pioneering solution in bone implant technology, potentially setting new standards for safety, efficacy, and longevity in orthopedic and dental implants.