Send to

Choose Destination
Proc Natl Acad Sci U S A. 2019 May 7;116(19):9552-9557. doi: 10.1073/pnas.1901788116. Epub 2019 Apr 18.

Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity.

Author information

School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom.
Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, West Midlands, CV4 7AL,United Kingdom.
Department of Biomedical Engineering, School of Biological Sciences, University of Reading, Reading, Berkshire, RG6 6AH, United Kingdom.
School of Life Sciences, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom;
Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, West Midlands, CV4 7AL, United Kingdom.


Membrane-potential dynamics mediate bacterial electrical signaling at both intra- and intercellular levels. Membrane potential is also central to cellular proliferation. It is unclear whether the cellular response to external electrical stimuli is influenced by the cellular proliferative capacity. A new strategy enabling electrical stimulation of bacteria with simultaneous monitoring of single-cell membrane-potential dynamics would allow bridging this knowledge gap and further extend electrophysiological studies into the field of microbiology. Here we report that an identical electrical stimulus can cause opposite polarization dynamics depending on cellular proliferation capacity. This was demonstrated using two model organisms, namely Bacillus subtilis and Escherichia coli, and by developing an apparatus enabling exogenous electrical stimulation and single-cell time-lapse microscopy. Using this bespoke apparatus, we show that a 2.5-second electrical stimulation causes hyperpolarization in unperturbed cells. Measurements of intracellular K+ and the deletion of the K+ channel suggested that the hyperpolarization response is caused by the K+ efflux through the channel. When cells are preexposed to 400 ± 8 nm wavelength light, the same electrical stimulation depolarizes cells instead of causing hyperpolarization. A mathematical model extended from the FitzHugh-Nagumo neuron model suggested that the opposite response dynamics are due to the shift in resting membrane potential. As predicted by the model, electrical stimulation only induced depolarization when cells are treated with antibiotics, protonophore, or alcohol. Therefore, electrically induced membrane-potential dynamics offer a reliable approach for rapid detection of proliferative bacteria and determination of their sensitivity to antimicrobial agents at the single-cell level.


bacterial electrophysiology; bioelectricity; cell biophysics; electrical signaling; rapid bacterial detection

Conflict of interest statement

Conflict of interest statement: Based on the findings of this work, a UK patent application for the approach of rapidly detecting proliferative bacteria using electricity has been filed and a spin-out company (Cytecom Ltd.) was founded with the support from the University of Warwick. The spin-out company and the corresponding author (M.A.) were awarded the funding for the commercialization of the technology from United Kingdom Research and Innovation (UKRI), the UK national funding agency. The authors clarify that the scientific conclusions that are presented in this study are not influenced by the activity of the spin-out company.

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center