An Engineered Nanocomposite Copper Coating with Enhanced Antibacterial Efficacy

Abstract

AbstractContaminated surfaces are a major source of nosocomial infection. To reduce microbial bioburden and surface‐based transmission of infectious disease, the use of antibacterial and self‐sanitizing surfaces, such as copper (Cu), is being explored in clinical settings. Cu has long been known to have antimicrobial activity. However, Gram‐positive microorganisms, a class that includes pathogens commonly responsible for hospital‐acquired infection such as Staphylococcus aureus and Clostridioides difficile, are more resilient to its biocidal effect. Inspired by inherently bactericidal nanostructured surfaces found in nature, an improved Cu coating is developed, engineered to contain nanoscale surface features and thus increase its antibacterial activity against a broader range of organisms. In addition, a new method is established for facilitating the rapid and continuous release of biocidal metal ions from the coating, through incorporation of an antibacterial metal salt (ZnCl2) with a lower reduction potential than Cu. Electrophoretic deposition (EPD) is used to fabricate these coatings, which serves as a low‐cost and scalable route for modifying existing conductive surfaces with complex shape. By tuning both the surface morphology and chemistry, a nanocomposite Cu coating is created that decreases the microbial bioburden of Gram‐positive S. aureus by 94% compared to unmodified Cu.