Lasers Could Turn Regular Metal Surfaces Into Bacteria Killers

A new laser treatment method could potentially turn any metal surface into a rapid bacteria killer just by giving it a different texture, researchers say. In a new study, they demonstrated that this technique allows the surface of copper to immediately kill off superbugs such as MRSA.

“Copper has been used as an antimicrobial material for centuries,” says Rahim Rahimi, an assistant professor of materials engineering at Purdue University. “But it typically takes hours for native copper surfaces to kill off bacteria. We developed a one-step laser-texturing technique that effectively enhances the bacteria-killing properties of copper’s surface.”

A laser prepares to texture the surface of copper, enhancing its antimicrobial properties. (Credit: Kayla Wiles/Purdue)

The technique is not yet tailored to killing viruses such as the one responsible for the Covid-19 pandemic, which is much smaller than bacteria.

Since publishing this work, however, Rahimi’s team has begun testing this technology on the surfaces of other metals and polymers used to reduce risks of bacterial growth, and biofilm formation on devices such as orthopedic implants or wearable patches for chronic wounds.

Giving implants an antimicrobial surface would prevent the spread of infection and antibiotic resistance, Rahimi says, because there wouldn’t be a need for antibiotics to kill off bacteria from an implant’s surface.

The technique might apply to metallic alloys also known to have antimicrobial properties.

Metals such as copper normally have a really smooth surface, which makes it difficult for the metal to kill bacteria by contact.

The technique Rahimi’s team developed uses a laser to create nanoscale patterns on the metal’s surface. The patterns produce a rugged texture that increases surface area, allowing more opportunity for bacteria to hit the surface and rupture on the spot.

Researchers in the past have used various nanomaterial coatings to enhance the antimicrobial properties of metal surfaces, but these coatings are prone to leach off and can be toxic to the environment.

“We’ve created a robust process that selectively generates micron and nanoscale patterns directly onto the targeted surface without altering the bulk of the copper material,” says Rahimi, whose lab develops innovative materials and biomedical devices to address healthcare challenges.

The laser-texturing has a dual effect: The technique not only improves direct contact, but also makes a surface more hydrophilic. For orthopedic implants, such a surface allows bone cells to more strongly attach, improving how well the implant integrates with bone. Rahimi’s team observed this effect with fibroblast cells.

Due to the simplicity and scalability of the technique, the researchers believe that it could easily translate into existing medical-device manufacturing processes.

The study appears in the journal, Advanced Materials Interfaces. Funding for the work came, in part, from Purdue’s School of Materials Engineering and the Wabash Heartland Innovation Network. Source: Purdue University. Original study DOI: 10.1002/ad

 

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