Laser-treated metals could be next step in fight against germs

Countless types of microbe that attack the human body can live on outdoor surfaces for days, meaning that frequently touched surfaces, such as door handles and handrails, can become locations where disease can spread at an alarming rate.

Disinfecting surfaces using a variety of chemicals, including alcohol concentrations and pesticide-related solutions, is one way to tackle the problem but the products are costly, both financially and in terms of time.

Researchers at Purdue University in the United States have now added to the options by creating a laser treatment that has the potential to turn any metal surface into an environment that is immediately hostile to bacteria, merely by altering the metal's surface texture.

The research has had promising results with scientists demonstrating that it was capable of manipulating the surface of copper to immediately kill bacteria, including MRSA.

The technique utilizes a laser to create small patterns on a nanoscale level on a metallic surface. The rugged texture increases the chance of a microbe rupturing on impact.

Imagine, instead of having a smooth runway for a plane to land on, large speed bumps are added to prevent a safe touchdown.

Copper's anti-bacterial qualities have been known for centuries which promoted its use as a physical currency when an object was needed to exchange between many hands.

However, instead of taking a matter of hours to break down as it would on untreated copper, bacteria instantly disintegrates on the microscopic rough texture that has received the laser treatment.

It should be noted, however, that this technique is not suitable yet to kill viruses such as the novel coronavirus that causes COVID-19 because viruses are much smaller than bacteria and would require a further refinement.

Viruses are so much smaller in fact, that a whole class of viruses, called Bacteriophages, exist with the sole purpose of infecting and reproducing within bacteria.

Led by Professor Rahim Rahimi, the research has instead shifted toward testing the technology on other materials, such as polymer plastics, to see if the same results in reducing the risk of bacterial growth can be achieved there too.

The application would be for devices such as orthopedic implants, including knee and hip replacements, and also for items such dressings and wearable implanted medical devices.

It is hoped that these would reduce the need for antibiotics and also help address growing concern about antibiotic resistance.

"The nice thing about our approach is it's not something we are adding to the surface, so there's no kind of additional material required, no antibiotics, no spray-coating," Rahimi said in a statement. "It's just modifying the native surface of the material. Antibiotic resistance is a big challenge right now, there are superbugs and bugs that are becoming more aggressive, antibiotics are not effective on them. We're developing technology that allows us to modify the surface of metal by laser surface modification to enhance antimicrobial properties."

The future of our war against microbes has been raging since before our inception as a species, and only in the last few centuries have we developed additional weapons in our arsenal against this common enemy, aside from our natural immune system.

It is vital that we continue to fund research and development in this field, so that scientists can continue to come up with newer and ever more ingenious solutions to continue this global battle against this seemingly infinite enemy.