Despite several measures taken to prevent contamination, pollutants like lead and mercury can still end up in the environment.
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Scientists reporting in the journal ACS Nano have engineered a self-powered nanosensor that could find small amounts of mercury ions and instantly report the outcome.
Mercury present in its Hg2+ form could become dangerous if consumed via contaminated water or food, so scientists have come up with several different mercury sensors. One of these was incorporated into a glove for on-site monitoring, but it failed to detect the ion present in small amounts and needed a regular supply of external power.
Rather, the focus is currently turning to self-powered systems like those impelled by the triboelectric effect, which is a form of static electricity. This electricity could keep the dveice running, and the voltage could also be utilized to signal the existence of a specific analyte.
Such devices are called triboelectric nanosensors (TENS). Hence, Zong-Hong Lin and collaborators wished to make a TENS that could precisely detect small amounts of mercury ions present just by touching a sample.
For TENS to be fabricated, the research group made use of an array of mercury-sensitive tellurium nanowires. This made their sensor highly selective, thereby enabling it to pick out its target even in complex samples.
The scientists mounted the TENS onto the fingertips of a robotic hand and frequently touched it into a sample solution. The modification in voltage was transmitted wirelessly to a smartphone in real time, according to the presence or absence of mercury ions.
Furthermore, the robotic sensor was successful in detecting ions in both naturally sourced and tap water with the same “tapping” technique. Also, it detected them in food, such as shrimp and an apple, after they had been spiked with the contaminant. The scientists say that their TENS could be the basis for similar devices to track other pollutants in a remote and safe manner.
The authors acknowledge financial support from the Young Scholar Fellowship Program by the National Science and Technology Council of Taiwan, the National Tsing Hua University Research Grant, and the Chung-Ang University Research Grant in 2022.
Detecting Mercury Ions With Just a Tap
Detecting mercury ions with just a tap | Headline Science. Video Credit: American Chemical Society.
Barman, S. R., et al. (2023) Triboelectric Nanosensor Integrated with Robotic Platform for Self-Powered Detection of Chemical Analytes. ACS Nano. doi.org/10.1021/acsnano.2c10770.