Modulated nanopillars via anodization of aluminum alloy and a possible application as antibacterial surfaces

Abstract

Natural nanostructures on the skin and wings of selected fauna have been reported to confer mechanobactericidal activity without the use of chemical antibiotics. It would be desirable to manufacture similar structures on man-made surfaces for medical and domestic use. In this paper, we show that aluminum anodization and wet etching can generate scalable, low-cost, and periodic nanostructures with high tunability. We present a comprehensive study of four types of nanopillars that produce bacteriostatic action in 1 h contact time against Escherichia coli, likely due to mechanical stress. Nanopillars with different dimensions were generated by modulation of temperature and voltage during the anodization of aluminum alloy AA6063. The surfaces with different aluminum oxide nanostructures decreased E. coli viability by ~47% on average vs smooth aluminum controls, demonstrating a robust and scalable approach to antibacterial nanostructured surfaces.