Traditionally, identifying a bacterium requires peering through a microscope. Researchers from TU Delft want to trade your eyes for your ears when identifying bacteria. This is possible because they’ve crafted nanoscale drums that convert bacteria’s movement into sound.

The technique originated when Delft researchers noticed something odd. If a living bacterium were on a graphene sheet, it would beat a distinctive pattern that you can detect with a laser. Each drumhead consists of two graphene sheets laid over an 8-micrometer-wide cavity. The sheets are less than a nanometer thick.

The sounds are due to the subtle motion of the tiny lifeform. Scientists have known about these motions, but previously had to measure them en masse. The tiny drums can respond to a single organism, typically about 1 to 10 micrometers in size.

Graphene makes this sensor possible because it is thin enough to behave like a drum with such a tiny force, yet also strong enough to support the bacterium. At first, the technique was simply to determine if antibiotics were killing the bacteria. However, they found that specific bacteria produced audio with unique spectrograms.

It is foolproof, but machine language models can identify among three common bacteria with nearly 90% accuracy. The next step is to reduce the high-tech research setup to something practical for a hospital or doctor’s office. Early prototypes are now in use in two hospitals.

We’ve seen the benefits of automated microscopes that can detect a particular disease. This technology, refined, could go even further.