New Graphene Coatings Combat Hospital Pathogens
Researchers in Switzerland have introduced ultra-thin, graphene-based coatings that can neutralize harmful hospital pathogens just using infrared light. Initial tests showed these materials successfully removed almost all traces of one drug-resistant bacterial strain and over 90 percent of another. This development could signify a pivotal moment in our ongoing struggle against antibiotic resistance.
The menace of drug-resistant microbes is no longer a future concern; it’s happening now. Traditional antibiotics are increasingly ineffective against a growing range of pathogens, and current antimicrobial coatings for medical devices also present challenges, such as potential allergic reactions and limited efficacy against viruses. Scientists at Empa, part of the ETH Domain, think nanomaterials might be a viable solution.
Leading the effort is the Nanomaterials in Health Lab in St. Gallen, managed by Peter Wick. He has over 20 years of experience examining how specialized materials interact with human biology. His team isn’t just refining existing technologies; they’re creating a brand new type of antimicrobial solution that can be activated by light.
Introducing Graphene-Based Coatings
The lab’s primary material was inspired by collaboration with a partner at Palacký University Olomouc in the Czech Republic. This team has been working with graphene, a form of carbon that consists of a single atomic layer. According to Giacomo Reina, a chemist who joined Wick’s lab in 2023, the medical applications were obvious and exciting.
The developed material is a mixture of graphene oxide and polyvinyl alcohol, a widely used plastic in the food industry. Remarkably thin, this coating is practically invisible, allowing it to be applied to medical equipment without altering its appearance. Reina has created four unique formulations, each aimed at enhancing specific properties, and these are believed to be the very first antimicrobial coatings based on graphene acid.
Setting high standards for themselves, the research team aimed for their nanomaterials to be not only antimicrobial but also compatible with tissue, environmentally friendly, and stable chemically. These requirements have been tough for existing metal-based coatings, such as those using silver, copper, or titanium dioxide, to meet fully.
The Role of Light in Activation
The antimicrobial action of this material involves a delicate chain reaction. When near-infrared light is applied—similar to what’s used in some hospital pain therapies—the coating heats up to around 44 degrees Celsius. This increase in temperature weakens the microbes, but the more prominent effect arises chemically; light instigates a reaction between the nanomaterial and nearby oxygen, producing highly reactive molecules called oxygen radicals that can attack bacterial surfaces.
Notably, infrared light can penetrate up to two centimeters into body tissue, which means it can activate coatings on implants from outside the body. Plus, the antimicrobial effect can be adjusted; Reina points out that the intensity can be modified simply by changing the amount of light energy applied, and using lasers can allow for even more precise targeting.
Wick described this exciting process as an innovative way to use physical energy to spark a chemical reaction with tangible biological results. Testing in the Biointerfaces Lab confirmed that this approach is effective: one of the materials wiped out nearly 100 percent of one bacterial strain and about 91 percent of another, outshining silver-based coatings that are currently in clinical use.
First Trials on Dental Implants
With proof of concept achieved, the team is now focusing on an urgent medical issue: infections associated with dental implants, which can, in severe cases, extend to the jawbone or even the whole body. Doctoral student Paula Bürgisser, starting her dissertation in summer 2025, is spearheading this project under the combined supervision of Wick and Professor Roland Jung from the University of Zurich’s Center for Dental Medicine.
The plan is straightforward. The part of a dental implant that interacts with gum tissue would get a pre-coating of this nanomaterial. Following implantation, infrared light would be used to eliminate surface microbes. This treatment could also be repeated during routine check-ups or whenever an infection is detected. Current testing shows that the material maintains its antimicrobial properties even after multiple activations without losing integrity.
However, the road to clinical application is still quite long. The goal is to partner with a private sector entity in the next three to four years to start clinical trials, though Wick warns that making these treatments widely available might take a decade or more. The lab is also looking into broader uses, such as developing nanomaterial-based sensors or cancer treatments, propelled by the belief that, in Wick’s words, foundational research keeps paving the way for future advancements.
