Biofilm-Protected Catheters Nanolaminated by Multiple Atomic-Layer-Deposited Oxide Films

The prevention of bacterial growth on biomedical devices is a challenging task in the medical discipline. For a long time, various studies have examined how to prevent the accumulation of bacteria on relevant surfaces, aiming to prevent infections and other complications, such as the rejection of the medical implant by the body, amputation, and death. Previous attempts to develop antibacterial surfaces mostly relied on wet chemistry approaches. Here, we demonstrate the preparation of coated nanoscale thick laminated films with unique combinations of metal oxides and with accurate control over the film thickness and composition by atomic layer deposition (ALD). We show that such anti-biofilm nanolaminated coatings diminish the number of bacteria on the catheters by several orders of magnitude; we demonstrate the effectiveness of the prepared films against Gram-negative—Escherichia coli (E. coli) sensitive and multidrug-resistant (MDR)—and Gram-positive—Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA)—bacteria. We found a synergistic effect between the various oxide layers deposited on the substrate: of all the studied films, a triple-layer film obtained by successive coating with 100 Al2O3 deposition cycles, followed by 900 ZrO2 and then 500 ZnO deposition cycles showed the best performance. This synergistic activity diminished the amount of E. coli and S. aureus on a coated silicone catheter by 3 orders and 1 order of magnitude, respectively. Our nanolaminate approach opens the path for further studies of potentially active coatings deposited by ALD and molecular layer deposition.