Bacterial sensors send a jolt of electricity when triggered

When you hit your finger with a hammer, you feel the pain immediately. And you react immediately.
But what if the pain comes 20 minutes after the hit? By then, the injury might be harder to heal.
Scientists and engineers at Rice University say the same is true for the environment. If a chemical spill in a river goes unnoticed for 20 minutes, it might be too late to remediate.
Their living bioelectronic sensors can help. A team led by Rice synthetic biologists Caroline Ajo-Franklin and Jonathan (Joff) Silberg and lead authors Josh Atkinson and Lin Su, both Rice alumni, have engineered bacteria to quickly sense and report on the presence of a variety of contaminants.
Their study in Nature shows the cells can be programmed to identify chemical invaders and report within minutes by releasing a detectable electrical current.
Such “smart” devices could power themselves by scavenging energy in the environment as they monitor conditions in settings like rivers, farms, industry and wastewater treatment plants and to ensure water security, according to the researchers.
The environmental information communicated by these self-replicating bacteria can be customized by replacing a single protein in the eight-component, synthetic electron transport chain that gives rise to the sensor signal.
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