Laser turns metal surfaces into bacterial killers

Researchers at Purdue University have discovered a laser treatment that textures metals that can transform almost any metal surface into a surface that quickly eliminates bacteria that contact it. Research published in journals Advanced material interface In April 2020, the common superbug transmission chain could be broken, reducing the number of infections caused by indirect spread through such surfaces.

Purdue engineers have developed a laser treatment method that can turn a metal surface into a rapid bacterial killer by simply giving the metal surface a different texture.

Why is surface disinfection important?

Bacteria are the causes of many diseases that make our lives difficult. Salmonella, boiling, and syphilis are just a few of the myriad types of harm that bacteria can cause to our bodies. One of the discomforts of bacteria is that most bacteria can survive on metal surfaces for long periods of time. In addition to the fact that most of the things we most often touch, such as doorknobs, bathroom fixtures and car keys, are made of metal, with a lot of potential pathogens waiting to jump on the skin,

The new process may change everything and turn the metal from a friendly hangout zone into a killing place for bacteria. It works by changing the texture of the metal surface using a laser. For example, copper is often used as a natural antimicrobial material. However, it takes hours to kill most bacteria on the surface. However, Purdue’s treatment dramatically accelerates the number of bacteria that die immediately upon contact, making them clinically useful.

The laser prepares the copper surface for texturing and enhances its antimicrobial properties. (Photo from Purdue University / Kayla Wiles)

Usually, the copper surface is smooth. This limits the area of ​​contact with bacteria. This leads to the number of dead bacteria. In the past, efforts have been made to use nanomaterial coatings to increase the surface area of ​​metals, but these have come off very easily and are often toxic.

How laser etching works to kill more bacteria

In a new approach, technology works on the metal itself. They use lasers to etch nanoscale grooves in metal, increasing its surface area and enhancing its antibiotic properties. Using native metal is much more rugged than existing technology and does not rub or hurt the environment.

“The good thing about our process is that it doesn’t add to the surface,” says Rahim Rahimi, Purdue University’s Materials Engineering department. “So no additional material of any kind is needed. No antibiotics, no spray coating. This only changes the original surface of the material.” Micron and nanoscale without changing much of the material We have created a robust process that selectively generates a pattern of the target directly on the target surface. “Research is underway to use this procedure with alloys with existing antimicrobial properties.

Treated surfaces have been shown to enhance bactericidal efficacy, even for aggressive pathogens that have developed resistance to traditional antibiotics such as MRSA. However, because these viruses are much smaller than bacteria, materials have not yet been developed that can eliminate viruses such as those that cause the COVID-19 pandemic. The etched surface has proven to be effective against both Gram-negative and Gram-positive bacteria.

Can medical implants be made more secure?

This technology goes beyond making the doorknob more hygienic. However, Rahimi and his team are working on adapting it for use in orthopedic implants and wearable wound patches. Implants are vulnerable parts of the body’s immune system because they are exogenous in nature. This means that additional measures must be taken to protect these susceptible areas. Antibiotics are usually used to prevent bacterial biofilm formation, which can lead to bacterial antibiotic resistance.

Purdue’s laser etching technique can prevent this by significantly increasing the antimicrobial properties of the implant surface without the use of antibiotics or anti-adhesive coatings that can slow the integration of the implant into the body.

Etching metal surfaces with nanoscopic patterns has another advantage. This greatly improves the hydrophilicity of the material. Some research has been done on hydrophilic surfaces and how they help heal: they control inflammation, help bone cells reattach more strongly, and improve the integration of implants with the body. It has been shown to improve and contribute to faster bone formation or bone regeneration. Rahimi and his team observed this behavior in fibroblasts. Also, when used in wound patches, hydrophilic surfaces help blood clot more efficiently and reduce the chance of infection.

Is laser etching commercially viable?

Due to its simplicity and scalable nature, Purdue’s pioneering laser etching process can be easily integrated into manufacturing operations already running on medical devices. Bacteria can range from annoying to life-threatening killers, and enormous amounts of work by medical teams is being devoted to preventing them. Laser etching offers a convenient way to significantly reduce this burden.