Researchers at the University of Toronto have engineered a surface coating made of flexible polymer chains that prevents bacteria-linked proteins from adhering — potentially cutting the risk of hospital-acquired infections without harsh chemicals.
A new surface coating developed by engineers at the University of Toronto could change how hospitals fight infection — by making surfaces so slippery that bacteria-binding proteins simply can’t hold on.
The coating, described in a study published in Chemical Engineering Journal, is made from polydimethylsiloxane (PDMS), a biocompatible silicone polymer already used in medical devices ranging from contact lenses to implants. The innovation lies not in the material itself, but in how it’s arranged: instead of being cross-linked into a rigid solid like conventional silicone rubber, the PDMS is configured into long, flexible chains that stand upright from the surface — like bristles on a brush.
Those bristle-like chains are key. Because they can bend and sway, the surface behaves in a “liquidlike” way that makes it extremely difficult for proteins to gain a grip.
Why Stopping Proteins Matters
Many hospital-acquired infections — a significant and persistent public health challenge — begin not with direct contact with bacteria, but with the protein-rich biofilms bacteria leave behind on surfaces. Kevin Golovin, an associate professor in mechanical & industrial engineering at the University of Toronto, explained the chain of events.
“Many infectious diseases are transmitted by touch,” Golovin, who leads the Durable Repellent Engineered Advanced Materials (DREAM) Laboratory at the University of Toronto, said in a news release. “The microbes that carry them typically release a sticky layer of proteins that enable their attachment to a surface. If you can stop those proteins from sticking, you can stop the disease from spreading.”
Currently, the go-to approach for keeping clinical surfaces sanitary involves repeated application of disinfectants. Golovin noted that method has real drawbacks.
“Right now, the simplest way to keep a surface clean and free of disease-causing microbes is to wash it with disinfectants like bleach,” he said. “But of course, it’s not great for the humans that work in these environments to be constantly exposed to these toxic products. And any time you’re using chemicals to kill pathogens, you’re increasing the chance of some strain evolving to be immune to them.”
How the Coating Was Tested
To evaluate the coating’s effectiveness, the team used bovine serum albumin (BSA), a protein derived from cow’s blood, as a stand-in for the adhesive proteins secreted by pathogens. Droplets of BSA dissolved in salt water were placed on the PDMS-bristle surface alongside surfaces coated with other non-stick materials.
Lead author Mehdi Sadeghi, a doctoral student, described what typically happens when such a droplet dries on an ordinary surface.
“As the droplet evaporates, what you normally see is that the BSA moves to the edges, forming something that looks like a coffee ring — a dark ring that stays behind on the surface even after all the water is gone,” Sadeghi said in the news release.
The PDMS bristle surface behaved very differently.
“But on the liquidlike surface covered in PDMS bristles, we didn’t see that. Instead, the ring shrunk along with the droplet, because the proteins just couldn’t stick,” Sadeghi added.
“All you’re left with at the end is a small dot of residue that just flakes off at the slightest touch: even a small puff of air is enough to make it fly off the surface. You could also wash it off with plain water, rather than harsh chemicals like bleach.”
The PDMS bristles also outperformed polyfluoroalkyl substances (PFAS) — a class of chemicals that includes Teflon — in resisting protein adhesion. That’s a notable finding, given that high-level PFAS exposure has been linked to health risks including cancer, making PDMS a potentially safer option for medical environments.
What Comes Next
The team’s next steps include collaborating with researchers who specialize in pathogenic bacteria to test whether the coating repels real bacterial proteins as effectively as it handles BSA. They are also in discussions with medical equipment manufacturers about licensing or commercializing the technology.
The research received partial funding from Meltech Innovation Canada Inc., part of the Medicom Group, a global producer of infection control products.
Golovin noted that scaling up production will be a key consideration going forward.
“The coating process is scalable, and its wider deployment will depend on optimizing manufacturing integration,” said Golovin. “Further assessment will be required to identify cost-effective pathways that align with the significant protective performance this technology enables, supporting potential expansion into both high-value equipment and single-use products. We’re very excited about the future possibilities.”
For students interested in materials science, biomedical engineering, or public health, the research illustrates how molecular-level design decisions can have wide-ranging implications for patient safety and antibiotic resistance — two of the most pressing challenges facing modern medicine.
Source: University of Toronto Faculty of Applied Science & Engineering