Microbubbles Scrub Biofilms Off of Medical Devices and Other Surfaces

Dentistry Today
Photo by L. Brian Stauffer.


Photo by L. Brian Stauffer.

About 80% of all medical infections originate from biofilms that invade the inner workings of hospital devices and implants inside patients, according to the University of Illinois at Urbana-Champaign. Eradication is difficult because traditional disinfectants and antibiotics cannot effectively penetrate the biofilm’s tough surface. Now, researchers at the school are using diatoms—the tiny skeletons of algae—loaded with an oxygen-generating chemical to destroy microbes.

“Most of us get those black or yellow spots in our showers at home,” said coauthor Hyunjoon Kong, PhD, MS, a professor of chemical and biomolecular engineering and a Carle Illinois College of Medicine affiliate. “Those spots are biofilms, and most of us know it takes a lot of energy to scrub them away. Imagine trying to do this inside the confined space of the tubing of a medical device or implant. It would be very difficult.”

Looking to nature and basic mechanics for a solution, the researchers developed a system that uses naturally abundant diatoms along with hydrogen peroxide and tiny oxygen-generating sheets of manganese oxide.

“We could have fabricated a particle using 3-D printers, but luckily nature already provided us with a cheap and abundant option in diatoms,” said coauthor and postdoctoral researcher Yongbeom Seo, PhD. “The species of diatom we selected are hollow, highly porous, and rod-shaped, providing a lot of surface area for the bubbles to form and a channel for the bubbles to escape. 

The chemical reaction between the hydrogen peroxide and manganese oxide nanosheets takes place within the empty space inside the diatom. The result is a flourish of microbubbles that flow through the tiny channel, propelling the rigid diatoms forward with enough force to break up the surface and internal structure of the biofilms, the researchers said. 

“We dope the particles with nanosheets of manganese oxide, then mix them with hydrogen peroxide and apply that to the surface of the biofilm,” Kong said. “Once the diatoms break through to the internal structure of the biofilm, they continue to expel bubbles and facilitate the entry of hydrogen peroxide, which is an effective disinfectant against bacteria and fungus.”

The researchers believe their success is a result of a decision to focus on the mechanical aspects of biofilm destruction, not the chemical aspects of simply killing microbes.

“We have arrived at a mechanistic solution for this problem, and the possibilities for this technology are endless,” said coauthor Simon Rogers, PhD, a professor of chemical and biomolecular engineering. “We are discussing our research with clinicians who have many exciting ideas of how to use this system that we did not even think of originally, such as the removal of dental plaque.” 

The study, “Diatom Microbubbler for Active Biofilm Removal in Confined Spaces,” was published by ACS Applied Materials & Interfaces.

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