Novel Microparticles Break Down Biofilms and Boost Antibiotic Activity

Biofilms are dense matrices of bacteria and proteins that shield microbes from disinfectants and drugs. They complicate wound care and the reprocessing of surgical instruments because standard agents often do not penetrate. Persistent biofilms raise infection risk and undermine cleaning protocols across care settings. To help address this challenge, engineers have developed bubble-generating microparticles and a wound dressing that mechanically disrupt biofilms.

At the University of Illinois Urbana-Champaign, researchers created cylindrical biosilica microparticles coated with manganese dioxide. When exposed to hydrogen peroxide, the catalyst generates tiny oxygen bubbles that accumulate within the hollow cylinders. As bubbles coalesce and burst, they propel the particles deeper into the matrix and mechanically break up the biofilm.

In laboratory tests on surgical tools, the team compared the biofilm remaining in serrations after the typical enzymatic-detergent-plus-autoclave protocol with results from the bubble-generating particles. The microparticles achieved similar or better efficacy than standard cleaning. Performance increased further when the particles were used at higher temperature, and the approach accessed confined areas—such as the teeth of forceps—where surfactants struggled to reach. The particles can also be combined with autoclaving.

For wound care, the group embedded the microparticles beneath a mesh that steadily releases hydrogen peroxide to form a “microblasting wound dressing.” In mouse wounds colonized with antibiotic-resistant biofilms typical of human infection, the dressing dislodged complex matrices, reduced biofilm burden, and accelerated healing. Treated wounds showed reduced inflammation and skin and hair regrowth. Disruption of the biofilm also enabled antibiotic penetration, preventing regrowth at doses ten times lower than standard.

Bubble formation, particle motion, and biofilm dispersal were monitored with high-speed imaging and Optical Coherence Tomography in collaboration with the Carle Illinois College of Medicine. Findings on particle design and instrument cleaning were reported in ACS Applied Materials and Interfaces. Results for the microblasting wound dressing were published in Advanced Science.

“The central lesson from this work is that treatment-resistant wounds can be understood as a biofilm problem. 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,” said Hyunjoon Kong, professor of chemical and biomolecular engineering at the University of Illinois Urbana-Champaign.

“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.

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