December 2, 2022

Scientists have created a method to prevent deadly infections without antibiotics

The newly developed method involves putting a small coating of zwitterionic material on a device and bonding it to the underlying substrate using UV light. The resulting barrier prevents bacteria and other harmful organic matter from attaching and causing infection.

UCLA researchers have created a new surface treatment that prevents bacteria from sticking to medical devices such as catheters and stents.

A hospital or medical clinic might seem like the last place you’d expect to get a bad infection, but nearly 1.7 million Americans do so each year, resulting in nearly 100,000 deaths from related complications. to infection and $30 billion in direct medical expenditure.

According to specialists, medical equipment such as catheters, stents, heart valves and pacemakers are the main culprits, accounting for two-thirds of all infections. Their surfaces are often covered with dangerous bacterial films. However, a unique surface treatment developed by a team led by scientists at the University of California, Los Angeles (UCLA) could help improve the safety of these devices while reducing the financial strain on the healthcare system.

The new technique, which has been tested in the laboratory and in clinical settings, involves depositing a thin layer of zwitterionic material on the surface of a device and permanently bonding this layer to the underlying substrate using irradiation with ultraviolet light. The resulting barrier prevents germs and other potentially harmful organic matter from adhering to the surface and infecting people.

The team’s findings were published in the journal Advanced materials May 19, 2022.

Medical devices with harmful microbes

Harmful microbes grow freely on implanted medical devices. A new method for applying a surface coating treatment to medical devices has the potential to improve their safety, reducing complications and patient deaths. Credit: Amir Sheikhi/State of Penn

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 aiming to achieve,” said Richard Kaner, Professor of Materials Innovation Dr. Myung Ki Hong at UCLA and lead author of the research. “The surfaces greatly reduced or even prevented the formation of biofilm.

Richard Kanner

Senior research author, Richard Kaner. Credit: Reed Hutchinson/UCLA

“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. With 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 injuries that may have been treated for decades can once kill them again.

“The beauty of this technology,” Kaner said, “is that it can prevent or minimize biofilm growth without the use of antibiotics. 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.

Reference: “A Easily Scalable, Clinically Demonstrated Zwitterionic Antibiofouling Surface Treatment for Implantable Medical Devices” by Brian McVerry, Alexandra Polasko, Ethan Rao, Reihaneh Haghniaz, Dayong Chen, Na He, Pia Ramos, Joel Hayashi, Paige Curson, Chueh- Yu Wu, Praveen Bandaru, Mackenzie Anderson, Brandon Bui, Aref Sayegh, Shaily Mahendra, Dino Di Carlo, Evgeniy Kreydin, Ali Khademhosseini, Amir Sheikhi and Richard B. Kaner, March 22, 2022, Advanced materials.
DOI: 10.1002/adma.202200254