Synergistic enhancement of antibacterial activity of Cu:C nanocomposites through plasma induced microstructural engineering.

• Developing Cu:C nanocomposite films using plasma cosputtering process for microstructure control. • Control of surface morphology and porosity for release of Cu ions. • Correlation of film composition and film structure with antibacterial activity. This study presents magnetron plasma co-sputtering process for the synthesis of carbon thin films embedded with Cu nanoparticles (NPs). Varying the working pressure and power density of Cu target, induces control over morphology as well as the amount of Cu ions release while interacting with bacterial aliquots. The crystallographic observations present the formation, growth and orientation of crystals in Cu NPs. Raman spectroscopy depicts that increase in working pressure contributes to the development of carbon matrix structure dominating sp3 hybridizations. The variation in chemical structure with varying the plasma conditions is studied by high resolution x-ray photoelectron spectroscopy. The antibacterial activity, observed against staphylococcus aureus (S. aureus) and Escheria coli (E. coli), is strongly related to the release of Cu ions from the films. The nanocomposite films releasing Cu ions ∼1.68 µg/g of the aliquot, completely inhibit the bacterial growth. Obtained excellent antibacterial activity of presented Cu embedded nanostructured carbon films proves these films as a promising candidate in bio-medical applications. [ABSTRACT FROM AUTHOR]