Copper-treated stainless steel promises to kill bacteria without antibiotics or chemicals
Marie Donlon | June 20, 2024A team of researchers from Georgia Tech has devised an electrochemical process that promises to offer new protection against bacterial infections without adding to growing antibiotic resistance.
According to the researchers, the new method relies on the natural antibacterial properties of copper in combination with small needle-like structures etched on the surface of stainless steel and designed to kill harmful bacteria including E. coli and Staphylococcus.
During the Tripathi's electrochemical process, current and an acid electrolyte etch nano-sized needle-like structures on the surface of stainless steel. The structures are able to destroy bacterial cells. Source: Small (2024). DOI: 10.1002/smll.202311546
The team suggests that the new approach could potentially reduce the need for chemicals and antibiotics in hospitals, kitchens and other environments where surface contamination can lead to illnesses. Further, the team believes the new approach could potentially save lives.
"Killing Gram-positive bacteria without chemicals is comparatively easy but tackling Gram-negative bacteria poses a significant challenge, due to their thick, multilayered cell membrane. And if these bacteria persist on surfaces, they can grow rapidly," explained Anuja Tripathi, the study's lead author. "I aimed to develop an antibiotic-free bactericidal surface effective against Gram-negative and Gram-positive bacteria."
Initially, the team created an electrochemical method for etching the surface of stainless steel, thereby puncturing nano-sized needle-like structures onto the surface that can subsequently puncture bacteria's cell membranes. An additional electrochemical process was then employed to deposit copper ions — which interact with the cell membranes and eventually compromise them — on the steel’s surface.
The team determined that the nanotextured stainless steel alone can destroy both Gram-negative and Gram-positive bacteria, but they opted to enhance the antibacterial activity with the addition of the copper coating to make it appropriate for surfaces that are highly contaminated.
Using just a thin layer of copper, which tends to be expensive, reportedly keeps the cost of this new approach down, the researchers explained.
In the lab, the new process resulted in a roughly 97% reduction of Gram-negative E. coli and a 99% reduction in Gram-positive Staphylococcus epidermis bacteria.
The researchers are suggesting that the stainless steel could be used for common tools in medical settings such as scissors or tweezers as well as for door handles, stair railings and sinks, for example. The process could also be appropriate for medical implants or the food processing and manufacturing industry.
An article detailing the new process, “Dual Antibacterial Properties of Copper‐Coated Nanotextured Stainless Steel,” appears in the journal Small.