Researchers at IIT, Guwahati, have developed a highly
responsive fluorescent sensor that can detect cyanide in water and human cells
using only an ultraviolet light source, according to officials.
The sensor is claimed to be effective in real-world samples
such as river water and breast cancer cells and is suitable for testing with
paper strips.
The research, published in the peer-reviewed Spectrochimica
Acta Part A: Molecular and Biomolecular Spectroscopy journal, not only
facilitates rapid cyanide detection but also paves the way for advanced
sensor-based smart devices using digital logic circuits.
The sensor changes colour and emits bright fluorescence in
the presence of cyanide, contributing to both environmental safety and forensic
investigations.
Cyanide is a highly toxic compound that is widely used in
industrial processes such as manufacturing of synthetic fibres, metal cleaning,
plastics, electroplating, and gold mining, according to G Krishnamoorthy, a
professor at the chemistry department of Indian Institute of Technology (IIT),
Guwahati.
"Improper disposal of cyanide often leads to its
release into the environment, contaminating soil and water sources. Consumption
of this contaminated water can disrupt oxygen supply in human body. Even a
small amount can cause severe health effects or death. Therefore, there is a
need to develop sensors that can detect even trace amounts of cyanide in
various materials," he said.
Fluorescent chemosensors are chemicals that light up under
light when they interact with specific chemicals. These sensors are popular due
to their ease of use, low cost, high sensitivity and potential for use in
biological systems. While many existing sensors work by dimming their light
(known as a "turn-off" response) when detecting substances, a
"turn-on" response -- where the signal brightens instead -- is often
more effective because it avoids false negatives and improves detection
clarity, he added.
The IIT, Guwahati, team has developed a "turn-on"
chemosensor that emits a weak blue fluorescence under ultraviolet light. In the
presence of cyanide, this fluorescence turns on and shifts to a brighter cyan
colour due to a chemical change in the molecule.
"This reaction is highly specific to cyanide,
especially in a carefully selected solvent system that includes water. What
sets this sensor apart is its versatility. The sensor works not only in lab
solutions but also in river and tapwater samples, with an accuracy of 75-93 per
cent.
"It can be embedded into paper strips for portable
testing and is effective in live cell imaging. In fact, the sensor was used to
detect cyanide inside biological cells, showing promise for applications in
environmental and forensic investigations," Krishnamoorthy said.
The research team conducted a combination of lab experiments
and advanced computational calculations called Density Functional Theory (DFT)
to confirm the sensing mechanism of the developed technology.
The researchers also demonstrated that this molecular sensor
could function like a basic logic gate, a key element in digital electronics.
This means it may have future use in developing smart, sensor-based electronic
devices that can detect harmful chemicals like cyanide in real time.
"As the next step, the research group is working on
developing a simple kit for testing a variety of analytes. This development
opens new possibilities for easy, rapid, and reliable cyanide detection in
environmental, medical, and industrial settings using a cost-effective tool and
basic ultraviolet light -- making it accessible for wide use," said
Bithiah Grace Jaganathan, a professor at the Department of Bioscience and
Bioengineering.
The team also inlcuded research scholars Mongoli Brahma,
Arup Das Kanungo, Minati Das and Sam P Mathew.
