Surface Activity-Tuned Metal Oxide Chemiresistor: Toward Direct and Quantitative Halitosis Diagnosis

Bad-breath sensor passes the sniff test

26 November 2021

A nanoparticle-based sensor that can directly detect minute traces of hydrogen sulfide in exhaled breath could be used as an early-warning system for ill health.

Bad breath, or halitosis, can be caused by regular build-up of microorganisms in the mouth between brushes, but it can also indicate certain serious medical conditions. It can be measured by quantifying the level of hydrogen sulfide in exhaled breath.

Researchers from KAIST and Samsung have teamed up to develop an electronic sensor that can directly measure halitosis when a user breathes on it.

The sensor was made by functionalizing tungsten oxide nanofibres with sodium and platinum to form Na₂W₄O₁₃ particles on the nanofibres. In the presence of hydrogen sulfide, the particles react to form Na₂SO₄, altering the resistivity of the nanofibre, which is detected by the electronics in the sensor.

The device could reliably differentiate hydrogen sulfide levels above and below 150 parts per billion in exhaled breath, the threshold for halitosis.

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References

1. ACS Nano 15, 14207–14217 (2021). doi: 10.1021/acsnano.1c01350