Broad spectrum antibacterial activity of nanostructured Cu oxide thin films grown via glancing angle sputtering deposition

The demand for antibacterial surfaces has intensified since the recent pandemic, underscoring the need to prevent microbial adhesion on high-contact surfaces. Metallic and metal oxide nanostructures exhibit intrinsic antibacterial properties, motivating the development of scalable, cost-effective fabrication routes for functional coatings. In this study, copper oxide (CuO) thin films were deposited by magnetron sputtering and further nanostructured via glancing angle deposition (GLAD). The films exhibited pronounced antibacterial efficacy, inactivating Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) with efficiencies over 98% after 8 h of exposure. Increasing the deposition angle enhanced surface roughness and hydrophobicity, which directly correlated with higher bacterial inactivation. Longer exposure further improved antibacterial performance, demonstrating time-dependent activity. These results establish GLAD-fabricated CuO thin films as a promising, industrially scalable strategy for next-generation antimicrobial surface coatings.