Reducing bacterial pathogens in hospitals remains something of continued importance, given the rate nosocomial infections. Nosocomial infections also referred to as healthcare-associated infections, are infection(s) acquired during the process of receiving health care that was not present during the time of admission.
In the U.S., according to the Centres for Disease Control and Prevention, each year approximately 2 million patients suffer with healthcare-associated infections in hospital settings, and nearly 90,000 are estimated to die.
One of the preventative measures subject to considerable research is with antimicrobial surfaces. A new study, reported in December 2021, concerns a variant of a copper surface eliminates bacteria in just two minutes.
The data, from RMIT University, shows that the surface eliminates bacteria more than 100 times faster and more effectively than standard copper. If such a surface was incorporated into hospitals, such as forming the structural frames of beds, door handles, and shelving, this could help combat the growing threat of antibiotic-resistant superbugs.
It is already established that copper can supress the growth or kill most strains of bacteria due to the release of ions released from the metal’s surface. A limitation with this antimicrobial action is that the process is relatively slow, taking around four hours to kill Staphylococcus aureus cells.
But this process is slow when standard copper is used, as RMIT University’s Distinguished Professor Ma Qian explained, and significant efforts are underway by researchers worldwide to speed it up.
In contrast, the newly fabricated surface has been demonstrated to kill more than 99.99 percent of bacterial cells in around two-minutes. This means that against Staphylococci the surface is120 times faster compared with conventional copper.
The basis of the new material is a special copper mould casting process that arranges copper and manganese atoms into specific formations. The manganese atoms are removed from the alloy using a scalable chemical process called “dealloying,” leaving pure copper full of tiny microscale and nanoscale cavities in its surface. This creates a copper material with a unique porous structure.
The manufactured surface is composed of comb-like microscale cavities. Within each comb are smaller nanoscale cavities that allow for a massive active surface area. The structure is also hydrophilic, which leads to bacterial cells struggling to hold their cell morphologies as they are stretched by the surface nanostructure. At the same time, the porous pattern allows copper ions to release faster.
The net effect is the structural degradation of bacterial cells. Given that bacteria have not developed resistance to copper, the surface could play an important role in helping address contamination.
The research appears in the journal Biomaterials, with the research paper titled “Robust bulk micro-nano hierarchical copper structures possessing exceptional bactericidal efficacy.”
