Bacteria can’t stick to a new type of nanoscale surface that could prove useful in food processing, medical, and shipping industries.
The technology uses an electrochemical process called anodization to create nanoscale pores that change the electrical charge and surface energy of a metal surface, which in turn exerts a repulsive force on bacterial cells and prevents attachment and biofilm formation.
Whereas a sheet of paper is about 100,000 nanometers thick, these pores can be as small as just 15 nanometers.
When the researchers applied the anodization process to aluminum, it created a nanoporous surface called alumina, which proved effective in preventing surrogates of two well-known pathogens, Escherichia coli O157:H7 and Listeria monocytogenes, from attaching, according to the study in Biofouling.
The study also investigates how the size of the nanopores changes the repulsive forces on bacteria.
A cheaper way to fight biofilms
“It’s probably one of the lowest-cost possibilities to manufacture a nanostructure on a metallic surface,” says senior author Carmen Moraru, associate professor of food science at Cornell University. Guoping Feng, a research associate in Moraru’s lab, is the paper’s first author.
Finding low-cost solutions to limiting bacterial attachments is key, especially in biomedical and food processing applications. “The food industry makes products with low profit margins,” says Moraru. “Unless a technology is affordable it doesn’t stand the chance of being practically applied.”
Anodized metals could be used to prevent buildups of biofilms—slick communities of bacteria that adhere to surfaces and are tricky to remove—in biomedical clean rooms and in equipment parts that are hard to reach or clean, Moraru says.
There are other strategies for limiting bacterial attachment to surfaces, including chemicals and bactericides, but these have limited applications, especially when it comes to food processing, Moraru says. With food processing, surfaces must meet food safety guidelines and be inert to food that they may contact.
Anodized metal could also have marine applications, such as keeping ship hulls free of algae.
Future work will investigate the repulsive effect of these surfaces on other bacteria, and the use of other anodized materials for this purpose.
The collaborating group from Rensselaer Polytechnic Institute is led by Diana Borca-Tasciuc, associate professor of mechanical, aerospace, and nuclear engineering.
The US Department of Agriculture funded the work.
Source: Cornell University