Aluminum based reflective nanolens arrays to improve the effectiveness of ultraviolet inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in water and a sucrose solution.

Aluminum based reflective nanolens arrays were developed via a series of aluminum electropolishing and anodization steps with subsequent selective dissolution of anodic aluminum oxide (AAO). The diameter of nanolenses (d) on arrays can be controlled by altering electrolytes and voltages used for aluminum anodization. The d values of arrays produced by anodization in 0.3 M oxalic acid at 40, 60, and 80 V, and in 1.0 M phosphoric acid at 100, 110, and 120 V were 71.94, 121.90, and 161.53 nm, and 220.16, 252.06, and 274.78 nm, respectively. The effectiveness of UV (254 nm) inactivation of Escherichia coli O157:H7 and Listeria monocytogenes at concentrations of 5-6 log CFU/mL in water and in a 10% (w/v) sucrose solution was improved using a nanolens array having a d value of 252.06 nm.