Researchers have discovered a method to halt bacterial infections using small electrical currents applied to the skin, eliminating the need for drugs. This innovative approach involves a skin patch designed for the first time to employ subtle electric currents for microbial control. The findings will be published in the Cell Press journal Device on October 24.
Researchers have discovered a method to halt bacterial infections using small electrical currents applied to the skin, eliminating the need for drugs. This innovative approach involves a skin patch designed for the first time to employ subtle electric currents for microbial control. The findings will be published in the Cell Press journal Device on October 24.
Bozhi Tian from the University of Chicago, a co-senior author of the study, expresses enthusiasm about the potential for drug-free treatments, particularly in cases of skin infections and wound healing, where antibiotic-resistant bacteria present a major challenge.
Historically, electricity has been utilized to influence mammalian cells, including human cells, in treating various diseases without relying on medications. For instance, electric impulses from pacemakers can regulate heartbeats by stimulating heart muscles, and retina prostheses use electricity to stimulate the retina, offering limited vision restoration.
Tian and his team explored the possibility of using electricity to target bacteria as an alternative to antibiotics, a method rooted in traditional treatments that have contributed to the growing crisis of antibiotic resistance. Overuse of antibiotics in both humans and livestock has led many bacteria to evolve resistance to current treatments, resulting in diminished efficacy. In fact, previous research suggests that drug-resistant infections were linked to approximately 1.27 million deaths globally in 2019.
The researchers aimed to assess the response of Staphylococcus epidermidis, a common skin bacterium, to electrical stimulation. While this bacterium is typically harmless and can even defend against pathogens, it poses risks when it enters the body through cuts or medical procedures, potentially causing severe infections. Recently, strains of S. epidermidis that resist all antibiotic classes have emerged.
Gürol Süel, another co-senior author from the University of California San Diego, notes that since Staphylococcus is part of the natural microbial ecosystem on our skin, it’s preferable not to eliminate it entirely, as its absence might lead to other issues.
The study revealed that small electric currents could trigger responses from S. epidermidis, but primarily in acidic conditions. The researchers refer to this phenomenon as selective excitability. While healthy skin is slightly acidic, chronic wounds tend toward neutral to basic pH levels.
Saehyun Kim, the lead author and a colleague of Tian’s at the University of Chicago, highlighted that the relationship between bacteria and electricity is not extensively studied, in part due to the unclear conditions needed for bacterial excitation. This newfound understanding of selective excitability could pave the way for controlling other bacterial species under various conditions.
In their experiments, the team applied a weak electric voltage of 1.5 volts—well below the safe level of 15 volts considered inconspicuous to humans—for short bursts of 10 seconds every 10 minutes over 18 hours. When conducted in the optimal acidic environment, this electrical treatment eliminated 99% of the biofilm, a clustered group of bacteria that can obstruct drug efficacy and contribute to chronic infections. In a neutral environment, however, the treatment exhibited no notable effects.
Further examination showed that following electrical treatment, S. epidermidis exhibited reduced expression of several genes, particularly those associated with antibiotic resistance and biofilm formation.
To facilitate skin wound treatment through the stimulation of S. epidermidis under appropriate conditions, the researchers developed a skin patch called Bioelectronic Localized Antimicrobial Stimulation Therapy, or BLAST. This patch consists of electrodes and a hydrogel that fosters an acidic environment. The device was tested on pork skin inoculated with S. epidermidis. Post an 18-hour treatment cycle, the researchers observed a significant reduction in biofilm coverage and nearly a tenfold decrease in S. epidermidis cells compared to untreated samples. Similar antimicrobial effects were noted when the device was applied to the surface of a catheter.
Tian suggests that with additional research into the safety and effectiveness of this approach, scientists could potentially create a wearable patch equipped with a wireless circuit to manage infections without the need for pharmaceuticals.
This research is funded by the Bill & Melinda Gates Foundation, the US Army Research Office, the National Science Foundation, and the National Institutes of Health.
