A hospital or medical clinic might be the last place you’d expect to pick up a nasty infection, but around 1.7 million Americans do so each year, leading to nearly 100,000 deaths from complications related to the virus. infection and approximately $30 billion in direct medical costs.
The biggest culprits, experts say – accounting for two-thirds of these infections – are medical devices such as catheters, stents, heart valves and pacemakers, the surfaces of which are often coated with harmful bacterial films. But a new surface treatment developed by a UCLA-led team of scientists could help improve the safety of these devices and ease the economic burden on the healthcare system.
The new approach, tested in the laboratory and in clinical settings, involves depositing a thin layer of what is called a zwitterionic material on the surface of a device and permanently bonding this layer to the substrate underlying the device. using ultraviolet light irradiation. The resulting barrier prevents bacteria and other potentially harmful organic matter from adhering to the surface and causing infection.
The team’s findings are published May 19 in the journal Advanced materials.
In the lab, the researchers applied the surface treatment to several commonly used medical device materials, then tested the modified materials for resistance to various types of bacteria, fungi, and proteins. They found that the treatment reduced biofilm growth by more than 80% – and in some cases up to 93%, depending on the microbial strain.
“The modified surfaces showed robust resistance against microorganisms and proteins, which is precisely what we were looking to achieve,” said Richard Kaner, Professor of Materials Innovation Dr. Myung Ki Hong at UCLA and lead author of the research. “The surfaces strongly reduced or even prevented the formation of biofilm.
“And our early clinical results have been outstanding,” Kaner added.
The clinical research involved 16 long-term urinary catheter users who switched to silicone catheters with the new zwitterionic surface treatment. This modified catheter is the first product made by a company founded by Kaner from his lab, called SILQ Technologies Corp., and has been cleared for use in patients by the Food and Drug Administration.
Ten of the patients described their urinary tract condition using the surface-treated catheter as “much better” or “very much better” and 13 elected to continue using the new catheter over the conventional latex and silicone options after the end of the study period.
“A patient came to UCLA a few weeks ago to thank us for changing her life — something that, as a materials scientist, I never thought possible,” Kaner said. “Her previous catheters became blocked after about four days. She was in pain and needed repeated medical procedures to replace them. Thanks to our surface treatment, she now comes every three weeks and her catheters are working perfectly with no encrustation or occlusion — a common phenomenon with its precedents.”
Such catheter-related urinary tract issues exemplify issues plaguing other medical devices, which, once inserted or implanted, can become breeding grounds for bacteria and the growth of harmful biofilms, said California member Kaner. NanoSystems Institute at UCLA who is also a distinguished professor of chemistry and biochemistry, and materials science and engineering. The pathogenic cells pumped by these highly resistant biofilms then cause recurrent infections in the body.
In response, medical staff routinely administer strong antibiotics to patients using these devices, a short-term solution that poses a longer-term risk of creating life-threatening, antibiotic-resistant “superbug” infections. The more widely and frequently antibiotics are prescribed, Kaner said, the more likely bacteria are to develop resistance to them. A landmark 2014 report from the World Health Organization recognized this overuse of antibiotics as an imminent threat to public health, with officials calling for an aggressive response to prevent “a post-antibiotic era in which common infections and minor wounds that have been treated for decades can once again kill.”
“The beauty of this technology,” Kaner said, “is that it can prevent or minimize biofilm growth without the use of antibiotics. It protects patients using medical devices — and therefore protects us all — from microbial resistance and the proliferation of superbugs.
The surface treatment’s zwitterion polymers are known to be extremely biocompatible and they absorb water very tightly, forming a thin moisture barrier that prevents bacteria, fungi and other organic materials from adhering to surfaces, said Kaner. And, he noted, the technology is highly effective, non-toxic and relatively inexpensive compared to other current surface treatments for medical devices, such as antibiotic-infused or silver-infused coatings.
Beyond its use in medical devices, the surface treatment technique could have non-medical applications, Kaner said, potentially extending the life of water treatment devices and improving the performance of lithium-ion batteries. ion.
Funding sources for the study included the National Institutes of Health, National Science Foundation, Canadian Institutes of Health Research, SILQ Technologies Corp. and the UCLA Sustainability Grand Challenge.
The study’s co-lead authors are Brian McVerry, Alex Polasko and Ethan Rao. McVerry helped develop this and other surface treatments during his doctoral research at UCLA with Kaner and co-founded SILQ Technologies Corp., where he is now Chief Technology Officer. Rao, director of research and development at SILQ, and study co-author Na He, a process engineer at SILQ, conducted research at UCLA in Kaner’s lab.
Other co-authors are Shaily Mahendra of the UCLA Samueli School of Engineering, professor of civil and environmental engineering, and Dino Di Carlo, professor of bioengineering and mechanical and aerospace engineering; Amir Sheikhi, assistant professor of chemical and biomedical engineering at Penn State University; and Ali Khademhosseini, CEO of the Terasaki Institute for Biomedical Innovation and former professor of bioengineering, chemical and biomolecular engineering, and radiological sciences at UCLA.