New Delhi, May 19 – In a groundbreaking development, researchers at the Indian Institute of Technology (IIT), Guwahati, have created a highly responsive fluorescent sensor capable of detecting cyanide in water and human cells using only ultraviolet light. This innovative sensor has shown effectiveness in real-world samples, including river water and breast cancer cells, and is designed for testing with paper strips.

The research findings were published in the peer-reviewed journal, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. The sensor not only allows for rapid detection of cyanide but also lays the groundwork for advanced sensor-based smart devices utilizing digital logic circuits.

Cyanide, a highly toxic compound commonly used in various industrial processes such as synthetic fiber manufacturing, metal cleaning, plastics, electroplating, and gold mining, poses significant health risks. Professor G. Krishnamoorthy from IIT Guwahati emphasized the dangers of improper cyanide disposal, which can lead to environmental contamination of soil and water sources. He noted that even small amounts of cyanide can disrupt oxygen supply in the human body, potentially causing severe health effects or death. This underscores the urgent need for sensors that can detect trace amounts of cyanide across different materials.

Fluorescent chemosensors, which emit light when interacting with specific chemicals, are favored for their ease of use, affordability, high sensitivity, and applicability in biological systems. Unlike many existing sensors that exhibit a “turn-off” response by dimming their light, the IIT Guwahati team developed a “turn-on” chemosensor. This sensor emits a weak blue fluorescence under ultraviolet light, which intensifies to a brighter cyan color in the presence of cyanide due to a chemical reaction.

The sensor’s specificity to cyanide is enhanced by a carefully selected solvent system, including water. Its versatility is notable, as it operates effectively not only in laboratory conditions but also in river and tap water samples, achieving an accuracy rate of 75-93%. Furthermore, the sensor can be integrated into paper strips for portable testing and has shown efficacy in live cell imaging, indicating its potential for environmental and forensic applications.

The research team employed a combination of laboratory experiments and advanced computational calculations known as Density Functional Theory (DFT) to validate the sensing mechanism of their technology. They demonstrated that this molecular sensor could function similarly to a basic logic gate, a fundamental component of digital electronics, suggesting future applications in smart, sensor-based electronic devices capable of real-time detection of harmful chemicals like cyanide.

Looking ahead, Professor Bithiah Grace Jaganathan from the Department of Bioscience and Bioengineering stated that the research group is working on developing a simple testing kit for a variety of analytes. This advancement promises to facilitate easy, rapid, and reliable cyanide detection in environmental, medical, and industrial contexts using a cost-effective tool and basic ultraviolet light, making it accessible for widespread use.

The research team also included scholars Mongoli Brahma, Arup Das Kanungo, Minati Das, and Sam P Mathew, contributing to this significant advancement in sensor technology.