The researchers used an electrochemical anodisation process to produce cylindrical nanopores between 15 and 100 nm in diameter on an aluminium surface. These surfaces were then incubated with cultures of E. coli and Listeria innocua before being examined for evidence of bacterial attachment and biofilm formation.
The results revealed that surfaces covered with nanopores of 15 to 25 nm diameter significantly inhibited both attachment and biofilm formation. The researchers have concluded that this is mainly due to “a synergy between electrostatic repulsion and surface effective free energy”, but an additional study indicates that the nanopore surfaces may also resist flagella-dependent attachment.
The technology is said to be inexpensive and could easily be used by the food and biomedical industries to create metallic surfaces that resist biofilm formation – a major cause of inadequate cleaning and sanitisation in food processing.
The study is published in the journal Biofouling and a full text version can be accessed here.