Antibacterial nanostructured copper coatings deposited on tantalum by magnetron sputtering

Direct synthesis of magnetron sputtered nanostructured Cu films with desired properties via plasma chemistry for their efficient antibacterial application

“…A specimen sample without thin film is used as the control. The bacteria are cultivated in the fresh medium of Luria‐Bertani broth (a medium containing 1% w/v tryptone, 0.5% w/v NaCl, and 0.3% w/v yeast extract) at a constant temperature of 37 °C (using the equipment LRH‐250 F) for 4.5 h with a fixed shaking rate of ∼140 rev min −1 . The cultivated/inoculated bacteria (or inocula) are then diluted for the standardization to attain an optical density equal to 0.5 at 600 nm.…”

“…This test is repeated for three times for all samples to confirm the antibacterial activity. The antibacterial activity (A in %) is calculated as follows: where N c and N s are, respectively, the numbers of the bacterial colony grown on the control samples (without film) and the sample with Cu films.…”

“…Therefore, there is the need of careful study on the synthesis methods of these biomaterials. Many deposition techniques such as chemical based polyol method, aerosol‐assisted chemical vapor deposition (CVD), combustion, solution process, thermal reductions, chemical reduction microwave irradiation method, laser ablation, magnetron sputtering (MS), and inductively coupled plasma processes have been used to prepare NS Cu based thin films with their suitability for antibacterial activity. Most of these methods (except the polyol method) use an oxygen‐free atmosphere to synthesize NS films to minimize the concern of oxidation of these materials.…”

“…Nevertheless, the reduction of material cost, as well as simple strategy to prepare and optimize the desired film properties of the direct and high rate deposition of NS Cu films for the best antibacterial activity using MS technique, could be interesting on inexpensive substrates. But, the available work on plasma‐based deposition to directly prepare metal NSs in the film grown‐matrix and details of antibacterial activity connected with film properties is still not satisfactorily clear . Also, there is no definite conclusion if the antibacterial activity is crucially controlled by the particular film properties or microstructures or the volumetric metal content of the films.…”

“…But, the available work on plasma‐based deposition to directly prepare metal NSs in the film grown‐matrix and details of antibacterial activity connected with film properties is still not satisfactorily clear . Also, there is no definite conclusion if the antibacterial activity is crucially controlled by the particular film properties or microstructures or the volumetric metal content of the films. Therefore, it is essential to investigate the factors affecting the film properties and their effects on antibacterial activity.…”