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Laser treatment gives metal surfaces the power to instantly kill bacteria

A laser treatment developed by engineers at Purdue University can be used to wipe out infectious bacteria as soon as they make contact with metal surfaces. The treatment works by simply changing the texture of a metal surface to strengthen its antimicrobial properties. 

Pathogenic bacteria can live on surfaces for hours or even days. The new technique from Purdue will make it possible to protect frequently-touched surfaces, like metal door knobs, from lingering germs.

The technique has not yet been adapted for killing viruses such SARS-CoV-2, which are much smaller than bacteria.

The researchers investigated whether their technique was effective in safeguarding copper surfaces. The study revealed that copper surfaces which had been treated were capable of instantly eliminating superbugs such as MRSA.

“Copper has been used as an antimicrobial material for centuries. But it typically takes hours for native copper surfaces to kill off bacteria,” explained study lead author Professor Rahim Rahimi. “We developed a one-step laser-texturing technique that effectively enhances the bacteria-killing properties of copper’s surface.”

Copper and other metals typically have a very smooth surface that is not ideal for killing bacteria on contact. Professor Rahimi’s team used a laser to create nanoscale patterns on the metal’s surface. This creates a rugged texture that increases surface area and improves the odds for bacteria to rupture as they hit the surface.

In past experiments, researchers have used various nanomaterial coatings to enhance the of metal surfaces. However, these coatings tend to ooze off and may 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,” said Professor Rahimi.  

Innovative materials and biomedical devices are developed in Professor Rahimi’s lab. The team has found that the laser-texturing not only improves antimicrobial properties, but also makes a surface more hydrophilic. With orthopedic implants, for example, a hydrophilic surface improves how well the implant merges with the bone by helping bone cells attach more firmly. 

The Purdue team explained that since the laser technique is simple and can be scaled up, it can easily be integrated into existing methods for manufacturing medical devices.

The study is published in the journal Advanced Materials Interfaces.

By Chrissy Sexton, Staff Writer


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