Electric-Field-Based Dressing Disrupts Biofilm Infection

A new study describes how an electric-field-based dressing disrupts mixed-species bacterial biofilm infection and restores functional wound healing.

Developed by researchers at Ohio State University (OSU, Columbus, USA) and Indiana University (Bloomington, IN, USA), the wireless electroceutical dressing (WED) involves patterned deposition of Silver (Ag) and Zinc (Zn) on the dressings fabric. When moistened, the WED generates a weak electric field (without any external power supply), and can be used as any other disposable dressing. The dressing electrochemically self-generates one volt of electricity upon contact with body fluids such as wound fluid or blood, which is not enough to hurt or electrocute the patient.

To test the efficacy of the dressing, the researchers used a porcine chronic wound polymicrobial biofilm infection model, with inoculation with Pseudomonas aeruginosa and Acinetobacter baumannii bacteria. The wounds were treated with a placebo dressing or WED twice a week for 56 days. The results showed that WED prevented and disrupted wound biofilm aggregates and accelerated functional wound closure by restoring skin barrier function. In addition, it battled biofilm-induced inflammation by circumventing nuclear factor kappa B activation and its downstream cytokine responses. The study was published on April 1, 2019, in Annals of Surgery.

“This shows for the first time that bacterial biofilm can be disrupted by using an electroceutical dressing,” said senior author Chandan Sen, PhD, of OSU. “This has implications across surgery as biofilm presence can lead to many complications in successful surgical outcomes. Such textile may be considered for serving as hospital fabric -- a major source of hospital acquired infections.”

Biofilms protect bacterial communities via extracellular polymeric substances (EPS) that form a matrix that serve as a diffusion barrier limiting antibiotic penetration and immobilizing antibiotics. The diffusive barrier also results in nutrient gradients that cause decreased growth and metabolic inactivity in parts of the biofilm community, allowing persister cells to arise, particularly in Gram-negative bacterial biofilms, as their cell membranes are composed of lipopolysaccharides that further limit antibiotic penetration.

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