The natural excitability in mammalian tissues has been extensively exploited for drug-free electroceutical therapies. However, it is unclear whether bacterial residents on the human body are equally excitable and if their excitability can also be leveraged for drug-free bioelectronic treatment. Using a microelectronic platform, we examined the electrical excitability of Staphylococcus epidermidis, a skin-residing bacterium responsible for widespread clinical infections. We discovered that a non-lethal electrical stimulus could excite S. epidermidis, inducing reversible changes in membrane potential. Intriguingly, S. epidermidis became excitable only under acidic skin pH, indicating that the bacteria were 'selective' about the environment in which they display excitability. This selective excitability enabled programmable suppression of biofilm formation using benign stimulation voltages. Lastly, we demonstrated suppression of S. epidermidis on a porcine skin model using a flexible electroceutical patch. Our work shows that the innate excitability of resident bacteria can be selectively activated for drug-free bioelectronic control.
Keywords: Bioelectronics; antibiotics; biofilms; electrical excitability; electrical stimulation; electroceuticals; membrane potential; microbial electrophysiology; opportunistic pathogen.