Electroceutical treatment of infected chronic wounds in a dog and a cat

DUAL ACTION ELECTROCHEMICAL BANDAGE OPERATED by a PROGRAMMABLE MULTIMODAL WEARABLE POTENTIOSTAT

Electrochemical bandages (e-bandages) can be applied to biofilm-infected wounds to generate reactive oxygen species, such as hypochlorous acid (HOCl) or hydrogen peroxide (H 2 O 2 ). The e-bandage-generated HOCl or H 2 O 2 kills biofilms in vitro and in infected wounds on mice. The HOCl-generating e-bandage is more active against biofilms in vitro , although this distinction is less apparent in vivo . The H 2 O 2 -generating e-bandage, more than the HOCl-generating e-bandage, is associated with improved healing of infected wounds. A strategy in which H 2 O 2 and HOCl are generated alternately-for dual action-was explored. The goal was to develop a programmable multimodal wearable potentiostat (PMWP) that could be programmed to generate HOCl or H 2 O 2 , as needed. An ultralow-power microcontroller unit managed operation of the PMWP. The system was operated with a 260-mAh capacity coin battery and weighed 4.6 grams, making it suitable for small animal experiments or human use. The overall cost of a single wearable potentiostat was $6.50 (USD). The device was verified using established electrochemical systems and functioned comparably to a commercial potentiostat. To determine antimicrobial effectiveness, PMWP-controlled e-bandages were tested against clinical isolates of four prevalent chronic wound bacterial pathogens, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Acinetobacter baumannii , and Enterococcus faecium , and one fungal pathogen of emerging concern, Candida auris . PMWP-controlled e-bandages exhibited broad-spectrum activity against biofilms of all study isolates tested when programmed to deliver HOCl followed by H 2 O 2 . These results show that the PMWP operates effectively and is suitable for animal testing.

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

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.

Anti-Biofilm Activity of a Tunable Hypochlorous Acid-Generating Electrochemical Bandage Controlled By a Wearable Potentiostat

Chronic wound biofilm infections represent a major clinical challenge which results in a substantial burden to patients and healthcare systems. Treatment with topical antibiotics is oftentimes ineffective as a result of antibiotic-resistant microorganisms and biofilm-specific antibiotic tolerance. Use of biocides such as hypochlorous acid (HOCl) has gained increasing attention due to the lack of known resistance mechanisms. We designed an HOCl-generating electrochemical bandage (e-bandage) that delivers HOCl continuously at low concentrations targeting infected wound beds in a similar manner to adhesive antimicrobial wound dressings. We developed a battery-operated wearable potentiostat that controls the e-bandage electrodes at potentials suitable for HOCl generation. We demonstrated that e-bandage treatment was tunable by changing the applied potential. HOCl generation on electrode surfaces was verified using microelectrodes. The developed e-bandage showed time-dependent responses against in vitro Acinetobacter baumannii and Staphylococcus aureus biofilms, reducing viable cells to non-detectable levels within 6 and 12 hours of treatment, respectively. The developed e-bandage should be further evaluated as an alternative to topical antibiotics to treat wound biofilm infections.