Stainless steel is an alloy frequently used in food and beverage industries, shared environments, and many medical devices. Bacterial adherence to this alloy can result in serious infections, which can cause morbidity and mortality as well as significant healthcare costs.
In this study, scientists at Georgia Tech have developed an electrochemical process that could offer new protection against bacterial infections without contributing to growing antibiotic resistance.
The method uses copper’s inherent antibacterial qualities to form minuscule needle-like structures on the surface of stainless steel to eradicate dangerous bacteria like Staphylococcus and E. coli. Because it is affordable and convenient, it could lessen the need for pesticides and medicines in kitchens, hospitals, and other places where surface contamination can cause serious illness.
Anuja Tripathi, the study’s lead author and a postdoctoral scholar in the School of Chemical and Biomolecular Engineering, said, “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 proliferate. “I aimed to develop an antibiotic-free bactericidal surface effective against Gram-negative and Gram-positive bacteria.”
Tripathi and her associates, Julie Champion, a William R. McLain Professor, and Thomas Pho, a former Ph.D. student, devised a one-two punch that gets past those obstacles and prevents bacteria from becoming resistant to medications.
The group initially created an electrochemical technique to etch stainless steel, producing needle-like structures on the surface that are nanoscale and capable of piercing the cell membranes of bacteria. After that, the researchers used a second electrochemical technique to deposit copper ions on the surface of the steel.
Through its interactions with cell membranes, copper eventually weakens them.
Tripathi said, “The nanotextured stainless steel can kill both Gram-negative and Gram-positive bacteria, but we wanted to enhance the antibacterial activity for highly contaminated surfaces. The copper coating on the nanotextured stainless steel gave us very high antibacterial activity.”
Although copper has been shown to have antibacterial qualities, its high cost prevents it from being utilized extensively to combat surface pollution. Tripathi’s method is less expensive and does not sacrifice the antibacterial properties of stainless steel because it only leaves a thin layer of copper ions on the material.
In the group’s investigation, the combined effects of the two assaults led to a 97% decrease in Gram-negative E. Coli and a 99% decrease in Gram-positive Staphylococcus epidermis germs.
This newly developed process could be useful in food service.
Tripathi said the approach could be easily incorporated into existing industrial processes, where different electrochemical coating methods are already used for stainless steel food storage containers.
Tripathi said future work will investigate if the copper-coated, nanotextured stainless steel is effective against other cells harmful to human health. She’s also interested in exploring whether the steel could be used for medical implants to help ward off infections.
Since it proved effective against troublesome E. coli, she’s hopeful.
“Reflecting on a recent E. coli outbreak in grocery stores in Calgary, Canada, I was particularly driven in my research, recognizing the urgent relevance and significance of combating such resilient bacteria on surfaces,” Tripathi said. “They can be difficult to eliminate. So, if we can effectively eliminate E. coli, we stand a good chance of eradicating many bacteria on surfaces.”
Journal Reference:
- Anuja Tripathi, Jaeyoung Park, Thomas Pho, Julie A. Champion. Dual Antibacterial Properties of Copper-Coated Nanotextured Stainless Steel. Journal Small. DOI: 10.1002/smll.202311546