Guwahati: Researchers from the Indian Institute of Technology (IIT) Guwahati have developed a highly responsive fluorescence sensor that can detect cyanide in water and human cells by using only UV light sources.
A team of research scholars led by Professor G. Krishnamoorthy of the Department of Chemistry says the sensor changes color and emits bright fluorescence when exposed to cyanide, providing a powerful tool for environmental safety, medical diagnosis and forensic investigations. It has been successfully tested on realistic samples including river water and breast cancer cells and is also compatible with portable paper strip tests.
Cyanide is a highly toxic chemical used in various industrial processes such as synthetic fiber production, metal cleaning, plastics, electroplating and gold mining. Improper disposal of cyanide can lead to environmental pollution, especially water and soil. Even minimal exposure to cyanide can seriously damage the body’s oxygen supply, leading to serious health problems or death. Therefore, detection and even trace amounts of cyanide are crucial to protecting the environment and human health.
Fluorescent chemical sensors emit light when interacting with specific target molecules, which are popular due to their simplicity, affordability, high sensitivity and utility in biological systems. Although many existing sensors detect harmful substances by reducing fluorescence (a “off” mechanism), a “turn-off” approach to signal lights up in the presence of a target provides better clarity and reduces the likelihood of false negatives.
The IIT Guwahati team developed a “turn to” chemical sensor-1H-imidazo-based on a compound called 2-(4′-diethylamino-2′-hydroxyphenyl)[4,5-b]Pyridine emits a faint blue fluorescence under ultraviolet light. In the presence of cyanide, fluorescence is exacerbated and transferred to cyan, indicating chemical conversion of sensor molecules. This reaction has high specificity for cyanide, especially in carefully selected water-based solvent systems. The sensor reached a detection limit of 0.2μm in aqueous samples, and the allowable limits for cyanide for drinking water and Indian cuisine are significantly lower than the allowable limits of the World Health Organization.
To verify the mechanism behind this detection, the researchers used a combination of laboratory experiments and computational techniques called density functional theory (DFT) calculations. According to Professor Krishnamoorthy, an expert in molecular fluorescence and spectroscopy, “What makes this sensor unique is its versatility. The sensor not only works in solutions prepared in labs, but also has the accuracy of 75% to 93% in real water samples such as rivers and tap water. It can be embedded in paper and gradually emerge in paper and perform well in port tocted. The cyanide in biological cells demonstrates its strong potential for application in the environment and forensic fields.”
The researchers also found that molecular sensors can mimic the functions of basic logic gates, which are the basic components in digital electronic circuits. This suggests the possibility of integrating these sensors into intelligent, sensor-based devices that can detect harmful substances such as cyanide in real time.
