GUWAHATI, 1 September 2025: Researchers at the Indian Institute of Technology (IIT) Guwahati have developed a novel nanosensor capable of detecting harmful water contaminants, including Mercury and tetracycline antibiotics, in less than 10 seconds. The sensor, created using milk protein and thymine, employs carbon dots that fluoresce under ultraviolet light. The glow dims upon contact with pollutants, providing a rapid and visible indication of contamination.

Led by Prof. Lal Mohan Kundu, Department of Chemistry, the research team, including scholars Pallabi Paul and Anushka Chakraborty, highlighted the urgency of detecting pollutants due to increasing urbanisation, industrial activities, and pharmaceutical overuse. Mercury, even in small amounts, is highly toxic and carcinogenic, while tetracycline antibiotics can contribute to antibiotic resistance and other health hazards if they enter water sources.

“The sensor can detect Mercury and tetracyclines at very low concentrations. Its biocompatibility also opens the door for potential use in biological fluids,” Prof. Kundu said. On a laboratory scale, the nanosensor detected Mercury at 5.3 nanomolar (1.7 parts per billion) and tetracyclines at 10–13 nanomolar, both below U.S. Environmental Protection Agency safety limits.

To enhance usability, the sensor has been tested in tap and river water, milk, urine, and serum samples. The team has also developed paper strips coated with the sensor, allowing on-the-spot testing with a simple ultraviolet lamp.

The research, published in Microchimica Acta, provides a low-cost, highly sensitive alternative to conventional water testing methods, with promising applications in both environmental monitoring and biomedical research. The findings are currently at the laboratory stage and require further validation before commercial use.

About IIT Guwahati: Established in 1994, IIT Guwahati hosts 11 departments, nine interdisciplinary centres, and five schools across engineering, science, healthcare, management, and humanities. The institute currently accommodates over 8,600 students and 455 faculty members. IIT Guwahati is ranked 7th among India’s best engineering institutions and has achieved global recognition in research and innovation, including a 42nd rank in ‘Research Citations per Faculty’ in the QS World University Rankings 2026.