New microparticles improve biofilm removal from wounds and surgical instruments

Newly developed microparticles can infiltrate stubborn bacterial matrices and release tiny oxygen bubbles to clean surfaces and wounds more efficiently than hydrogen peroxide or other cleaning agents alone, researchers at the University of Illinois Urbana-Champaign report. In two papers they demonstrated the bubble-generating particles' ability to clean tenacious biofilms from surgical instruments and, when embedded within bandages, to clean infected wounds and speed healing.

As well as describing the microparticles in the first paper, published in the journal ACS Applied Materials and Interfaces, the researchers demonstrated the microparticles' ability to clean stubborn biofilms from surgical instruments.

The Illinois team compared the biofilms remaining within the serrations of surgical instruments after the typical protocol with those remaining after treatment with the microparticles. They found a similar or better efficacy with the microparticles. As an additional boost, the microparticle cleaning can be combined with autoclaving, Kong said.

"We show a five-fold reduction in remaining biofilm with our particles at higher temperature. And then on top of that, we saw that in the teeth of forceps - a model surgical instrument - the enzymatic surfactant does not easily go into confined areas and cannot remove the bacterial film from those areas. But with our particle system, we actually could remove the films in those spaces. That's a huge difference," Kong said.

In the second paper, published in the journal Advanced Science, the researchers embedded the microparticles into bandages to dress persistent wounds, another place where biofilms frequently form.

"Chronic wounds affect millions of patients, including about 10.5 million Medicare beneficiaries in the United States, and biofilms are found in 60-80% of chronic wounds," Kong said.

The researchers embedded the microparticles in the bandages beneath a mesh that steadily releases hydrogen peroxide, activating the particles. They called the bandage assembly a "microblasting wound dressing," as it localizes the microbubble generation at the wound site, continually blasting the wound surface with tiny scrubbing bubbles, said postdoctoral researcher Yujin Ahn, the first author of the paper.

Just as with the surgical instruments, the microparticles and the bubbles they generated dislodged complex biofilms on the wound surface. On mouse wounds with antibiotic-resistant films of the kinds seen often in human patients, the microblasting wound dressing greatly reduced the biofilm present and accelerated healing, with reduced inflammation and skin and hair regrowth, Ahn said. It also enabled antibiotics to penetrate the disrupted biofilm, preventing regrowth even at antibiotic doses ten times lower than standard.

"The central lesson from this work is that treatment-resistant wounds can be understood as a biofilm problem," Kong said. "Dense polymicrobial biofilm matrices limit drug penetration and shield bacteria from therapy. By confining self-propelling bubble generators beneath a hydrogen peroxide-releasing mesh, we remove the biofilm barrier, improving antibiotic efficacy while reducing inflammation during wound healing."

Next, the researchers plan to test their microparticle technology on cleaning surgical endoscopes, whose inner hollow tubes make for very difficult cleaning, as well as applying the bandages to chronic wounds in large animals, Ahn said. The researchers also have obtained a patent for the bubble-generating microparticle technology and are working with partners to explore manufacturing at larger scales.

"We think this has many applications, both clinical and industrial. Biofilms form in many places, and this is a technology that can disrupt them mechanically without harsh chemicals or special equipment," Kong said.

The U.S. National Science Foundation, U.S. National Institutes of Health, the Chan Zuckerberg Biohub Chicago and the Korean Ministry of Trade, Industry and Energy supported this work.

Source:

University of Illinois at Urbana-Champaign

Journal reference: