A robotic hand equipped with a tiny sensor can detect harmful mercury ions in water or food by poking them.
The considers mercury a chemical of major public health concern because it can cause health issues if consumed via contaminated water or animals that have been exposed to it. Methods for detecting mercury in food and the environment exist, but most involve complicated and costly laboratory equipment and sometimes long processing times. So at National Tsing Hua University in Taiwan and her colleagues decided to develop a quicker and simpler approach.
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Their sensor is a small patch containing extremely thin wires, a thousand times thinner than a human hair, made from the metal-like material tellurium. Mercury ions bind to the tellurium wires. When the wires touch other objects, they experience the triboelectric effect, where their electric voltages change.
To test the sensor, Barman and her colleagues attached it to the finger on a robotic hand. They then used it to prod water from a lake in Taiwan and a tap in the lab, as well as a mercury-contaminated apple, shrimp and spinach leaf.
Barman says that the new sensor can detect a few nanomoles of mercury ions in a litre of water, which is sensitive enough to pick up on commonly reported pollution levels in lakes and seafood. The robotic hand can be preprogrammed to be used in areas that are dangerous for humans or where it is inconvenient for them to go, like in mining areas, she says.
at Simon Fraser University in Canada says that because the new sensor doesn鈥檛 confuse mercury ions with similar particles, it could be accurate in environments with many sources of pollution. Kim and his collaborators built one of the first , but he says the new one is more accurate. The most useful robot with chemical-sensing hands, however, would have a sensor for a different ion on each finger, he says.
ACS Nano
