Image: H2O2 propelled diatoms can disrupt biofilm colonies (Photo courtesy of ACS).
A new antiseptic system harnesses the power of microbubbles to propel rigid diatoms through the surface of tough biofilms, disrupting their internal structure.
Researchers at the University of Illinois at Urbana-Champaign (UIUC; USA), the Korea Institute of Industrial Technology (KITECH; Gyeonggi-do, South Korea), and other institutions have developed a system that uses hollow, cylinder-shaped diatom biosilicas and blended hydrogen peroxide (H2O2) and manganese oxide (MnO2) nanosheets. In an antiseptic H2O2 solution, the diatoms discharge oxygen gas bubbles, becoming self-motile and propelling the rigid diatoms forward with enough force to fracture the matrix of the biofilm.
The disrupted extracellular polymeric substances (EPS) allow the H2O2 molecules to diffuse into the biofilm structure, delivering a powerful antiseptic deathblow to the microbes and fungus living inside. According to the researchers, the H2O2 microbubble scrubber could potentially provide a unique and powerful tool to augment current efforts to disinfect and clean a wide array of biofouled products and devices. The study was published on August 14, 2018, in Applied Materials and Interfaces.
“Most of us get those black or yellow spots in our showers at home. Those spots are biofilms and most of us know it takes a lot of energy to scrub them away,” said study co-author professor of chemical and biomolecular engineering Hyunjoon Kong, PhD, of UIUC. “Imagine trying to do this inside the confined space of the tubing of a medical device or implant. It would be very difficult.”
Biofilms protect bacterial communities in part because the EPS that form the biofilm matrix serve as a diffusion barrier, limiting antibiotic penetration. The diffusive barrier also results in nutrient gradients, causing decreased growth and metabolic inactivity in parts of the biofilm community, allowing persister cells to arise. Persister cell formation is most observed in Gram-negative bacterial biofilms, as their cell membranes are composed of lipopolysaccharides that further limit antibiotic penetration.
University of Illinois at Urbana-Champaign
Korea Institute of Industrial Technology