WATCHING a protozoan version of synchronised swimming could provide a low-cost way of detecting toxins in water.
Many species of protozoa are covered in hair-like cilia that beat in a coordinated way to propel them through a fluid. Chemicals in the fluid can interfere with the transport of calcium to the cilia, with different chemicals altering the microbes’ swimming style in different ways, says Robert Curtis at Petrel Biosensors, a spin-out of the in Massachusetts.
Curtis’s team placed protozoans in test solutions containing different common toxins, and used a camera to assess the resulting swimming patterns. Using these as reference points, the team is now developing a device that uses algorithms to match the microbes’ swimming style in a water sample to the toxin present, if any. “You can see very distinct patterns of swimming, so we can say if it’s a heavy metal toxin or a phospho-organic toxin,” Curtis says.
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The company says the instrument will cost around $15,000. Each test will cost $1 to $2 and take around 30 seconds, unlike tests with existing devices, which can cost up to $400 and take two to three days, says Curtis.
