Activity of a hypochlorous acid‐producing electrochemical bandage as assessed with a porcine explant biofilm model

Abstract

The activity of a hypochlorous acid‐producing electrochemical bandage (e‐bandage) in preventing methicillin‐resistant Staphylococcus aureus infection (MRSA) infection and removing biofilms formed by MRSA was assessed using a porcine explant biofilm model. e‐Bandages inhibited S. aureus infection (p = 0.029) after 12 h (h) of exposure and reduced 3‐day biofilm viable cell counts after 6, 12, and 24 h exposures (p = 0.029). Needle‐type microelectrodes were used to assess HOCl concentrations in explant tissue as a result of e‐bandage treatment; toxicity associated with e‐bandage treatment was evaluated. HOCl concentrations in infected and uninfected explant tissue varied between 30 and 80 µM, decreasing with increasing distance from the e‐bandage. Eukaryotic cell viability was reduced by an average of 71% and 65% in fresh and day 3‐old explants, respectively, when compared to explants exposed to nonpolarized e‐bandages. HOCl e‐bandages are a promising technology that can be further developed as an antibiotic‐free treatment for wound biofilm infections.

HOCl-producing Electrochemical Bandages for TreatingPseudomonas aeruginosa-Infected Murine Wounds

“…10 HOCl-producing e-bandages were tested for 48 hours against 2-day P. aeruginosa biofilms in an in vivo murine dermal wound model. In confirmation of previous tests of this HOCl-producing electrochemical approach, 12, 13, 15, 24 polarization of e-bandages resulted in more HOCl within wounds in comparison to non-polarized and Tegaderm-only controls (161 vs. 67 and 81 μM, respectively) after 48 hours of treatment.…”

“…Previously, we used microelectrodes to show that these e-bandages produce HOCl at the working electrode, and that the HOCl can penetrate into biofilms and explant tissue. 15, 20 Here, free chlorine spectrophotometer test kits (TNT866; Hach Company, Ames, IA) were used to measure total HOCl content in wounds. Wounds harvested from mice treated with polarized e-bandages had higher levels of HOCl than those treated with non-polarized e-bandages (p = 0.170) or Tegaderm alone (p = 0.0045) ( Table 1 ).…”

“…The e-bandage and wearable potentiostat are described in previous studies. 15, 16 Briefly, the e-bandage comprises three integrated electrodes: functional circular carbon fabric working and counter electrodes, each with surface areas of 1.77 cm 2 (Panex 30 PW-06, Zoltek Companies Inc., St. Louis, MO), along with a silver/silver chloride (Ag/AgCl) wire that functions as a quasi-reference electrode (QRE). The operational potential of the working electrode is maintained at +1.5 V Ag/AgCl using a wearable potentiostat.…”

Evaluation of Treatment of Methicillin-ResistantStaphylococcus aureusBiofilms with Intermittent Electrochemically-Generated H2O2or HOCl

“…These results indicate that treatment using electrochemically generated H 2 O 2 is not desirable immediately after HOCl generation for biofilm control. Electrochemical generation of these species depends on polarization potential; this electrochemical process is beneficial because it allows for low concentrations to be generated over long periods of time without being cytotoxic (41, 43). Since longer e-bandages treatment times would result in accumulation of higher concentrations of these species, shorter treatment times may be desirable.…”

“…HOCl microelectrodes were constructed by following a published protocol (41). Briefly, a two-electrode system, including a platinum working electrode to sense HOCl concentration, and an external reference electrode (Ag/AgCl in saturated KCl) were used.…”