Heavy metal contamination in the groundwater table is one of the major concerns standing in front of humanity. There are many impacts one can observe due to the presence of heavy metals in the water. The biggest source from where this water gets contaminated is the plants. Many inputs, along with pesticides, contain these metals that are poisonous to the human body. Hence, it is essential to detect and identify these metals so that scientists can devise proper mitigation strategies. MIT scientists have recently developed a nano bionic optical sensor to detect and monitor toxic heavy metal arsenic in real-time.
What are optical sensors?
Sensors are the transducers that convert one form of energy specifically into electrical energy. The final output from the sensors is the electrical or electronic signal. As the name suggests, an optical sensor transforms light rays into an electrical or electronic signal. Hence, an optical sensor measures a physical quantity of a light ray and then brings it into the form with which instruments can read the signals. An optical sensor precisely reads the change in the light during a photoelectric trigger. As a result, it reads the mutation in the light.
Impact of Arsenic on Plants & Soils
There are two arsenic forms – arsenate and arsenite that plants take up quickly due to their affinity. After entering into the plant cells, arsenate converts into arsenite, the more toxic forms among the two. Then, the arsenite starts disrupting the metabolism in the plant cells. As a result, it stimulates plants to respond with various mechanisms, including phytochelatin, hyperaccumulation, and antioxidant defense system. If not detoxified, arsenic may trigger a sequence of reactions. These reactions may lead to the growth of inhibition, disruption of photosynthetic and respiratory systems, and stimulation of secondary metabolism. Thus, arsenic can accumulate to levels that could harm the physicochemical properties of soils and lead to soil fertility and crop yield loss. The problem with arsenic is that it remains in the environment for a prolonged period.
Impact of Arsenic on Humans
The primary toxicity of arsenic lies with the inorganic arsenic. Any consumption of a large volume of inorganic arsenic may lead to gastrointestinal symptoms such as vomiting. Some of the other effects on humans are:
- Reduction in blood production due to the loss of red blood cells (RBCs).
- Change in skin color.
- Tingling and loss of sensation in the limb
- More prolonged exposure may lead to Blackfoot disease (blood vessels in the lower limbs get damaged, leading to gangrene).
- Heart attack, high blood pressure may cause damage to the brain.
Researchers from DiSTAP (Disruptive and Sustainable Technologies for Agricultural Precision) at SMART (Singapore-MIT Alliance for Research and Technology) have developed nanoparticles that monitor and detect arsenic’s presence in the plants. This detection of arsenic happens in the leaf tissue. The researchers have presented their model in a paper titled, “Plant Nanobionic Sensors for Arsenic Detection.” A reputed journal, Advanced Materials, published this with the title mentioned above. Researchers tested the sensor to detect arsenic in rice, spinach, and a fern species, Pteris cretica, that hyper accumulates arsenic.
Working Principle of Sensor
The newly developed sensor works on the principle of fluorescence intensity of arsenic. After it detects arsenic, the optical sensor exhibits the fluorescence property to monitor the internal dynamics of arsenic injected into the tissues of the plants from the soil. The sensor enables plants to become self-powered arsenic detectors from the nearby environment. So, it makes a significant upgrade of the equipment-intensive arsenic sampling methods. The use of nanoparticles has enhanced the precision in the detection at the nano-scale. Nanobionic optical sensors can detect very low arsenic concentrations, as low as 0.2 parts per billion, which is 2% of the regulatory limit (10 parts per billion).
The arsenic detection in the early stage will help the researchers and scientists develop preventive plans. It may also enhance the research and development of new kinds of arsenic-resistant crops after understanding the pattern of their presence in the plants. Researchers should develop plans to harness this sensor to monitor the sequential genomic mutation when arsenic enters the tissues. Hence, the new nano bionic optical sensor has opened gates for sustainable agricultural practices.
Kellie Minton arrived on the cyber security scene in the early 2000s when virus and malware were still new and slowly evolving. Her longtime affair with writing with an interest in the cybersecurity industry, combined with her IT degree, has contributed to experience several aspects of security suite industry such as blogging at norton.com/setup .