Super nano-copper coating to kill bacteria

A team of University of British Columbia researchers has designed a new copper coating that can kill bacteria more quickly and in greater quantities than current chemistries and could soon be available for hospitals and other high-traffic facilities.

The group, led by Amanda Clifford, an assistant professor in the department of materials engineering, has designed a nano-copper coating that includes bacteria-killing nanoscale features and zinc.

Although current formulations made of pure copper are antibacterial and self-sanitizing and can kill certain types of bacteria with thicker cell walls – gram-positive bacteria – it actually does it much more slowly than with bacteria with thinner cell walls – gram-negative bacteria.

UBC's new nano-copper has two features that make it more effective – tiny bumps that can kill bacteria by rupturing their cell walls; and zinc, which is also an antibacterial that selectively oxidizes in the presence of copper and helps kill bacteria more quickly compared to pure copper alone.

"Use of our coating could significantly reduce the incidence of contracting bacterial infections from high-touch surfaces in healthcare facilities, such as doorknobs and elevator buttons, since it kills bacteria using multiple approaches," said Clifford. "As it contains less copper than other existing coatings or whole copper parts, it would also be cheaper to make."

The team found that the material took just one hour to kill roughly 99.7% of Staphylococcus aureus – a gram-positive pathogen commonly responsible for hospital-acquired infections – compared with two hours for pure copper.

"Not only does this coating kill pathogens faster than pure copper, it helps to ensure antibiotics remain effective," added Clifford. "By using this new formulation, we're killing pathogens before patients become infected and need to use antibiotics against them, slowing the rise of antibiotic resistance."

Over the years, through the use of antibiotics, bacterial infections have been significantly reduced. Yet, due to a heavy dependence on them to alleviate healthcare-associated infections and other illnesses, bacteria have often evolved to become immune or extremely resistant to them.

The use of antibacterial coatings such as the one developed by the UBC researchers could slow the reliance on antibiotics and the eventual super-bacteria that have been evolving as a result of.

The researchers have filed a provisional patent for the coating and fabrication process, which is described in the recently published paper in "Advanced Materials Interfaces."

"This is currently targeted for hospitals and health care settings because those locations are where the antibiotic-resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), are an issue," finished Clifford. "We also don't want to be at a place where we can't use antibiotics."

The team plans to further evaluate the material against other pathogens, such as viruses, with hopes of eventually commercializing their work.