Dielectica traverses through the literature on this topic – and summarizes as they appear.
Key Words: Arsenic, Ground Water, Carbon Nanotube, NIR light emission
India: Arsenic is a chemical element and depending on its constituent form it can have different levels of toxicity. The natural existence of Arsenic in ground water is known as Arsenic pollution and is considered as a severe threat to mankind. It is estimated that arsenic poisoning of drinking water has affected more than 70 countries worldwide including India. Arsenic poisoning can create serious problem to human health and can lead to various diseases right from skin infection to cancer. The leading agencies like World Health Organization and Food and Agriculture Organization of the United Nations have recommended the limiting values of arsenic in drinking water and irrigation water as 10 ppb and 100 ppb respectively [1]. Although Arsenic level in surface water is less, its higher concentration is found in ground water. Since human life is largely dependent on ground water, Arsenic detection and removal require severe attention. The scientific community has been continuously engaged in this purpose. However, cost effect methods are encouraged so that people from all sections of society can avail the technique.
Researchers from Massachusetts Institute of Technology (MIT), USA have invented that engineering of living plants can lead to natural and non-destructive technique to detect Arsenic in the environment [1]. Prof. M. S. Strano and the co-workers have demonstrated that some living plants when integrated with particular nanomaterials can indicate the presence of Arsenic in below ground and hence can work as natural and selfpowered Arsenic detectors. In general few wild-type plants like Pteris Cretica have the natural ability to pre-concentrate and extract Arsenic from the belowground. The MIT research group has fabricated a nanomaterial which is DNA-wrapped single-walled carbon nanotube (SWNT). This particular nanomaterial emits near-infrared (NIR) light and serve as the nanosensor for Arsenite (form of Arsenic in aqueous environment) detection. In this study, the DNA-wrapped SWNTs have been incorporated into the leaf tissues of wild-type plants. While the Arsenite molecules taken up by the roots of the plants from belowground are transported through the plant vasculature and are pre-concentrated in the leaf. Considering these facts, the presence of Arsenite has been detected through the modulation of light emission intensity of DNA-wrapped SWNTs by whole plant or cellular imaging. Using this technique the researchers have been able to detect as low as 0.2 ppb of Arsenic which is well below the recommended level [1]. Indeed the reported study is very exciting as it can lay foundation of natural, self powered, ultrasensitive and universal Arsenic detectors.
Sources:
[1] T. T. S. Lew et. al. Class. Adv. Mater. 2005683 (2020).
https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202005683