Researchers at the Indian Institute of Technology (IIT) Guwahati have created a novel nanosensor capable of detecting Mercury and harmful antibiotics in water in under 10 seconds, a breakthrough that promises rapid and sensitive monitoring of toxic contaminants.
The technology, led by Prof. Lal Mohan Kundu of the Department of Chemistry, uses carbon dots derived from milk protein and thymine, a nucleobase, to identify pollutants with high precision. Mercury, even in trace amounts, is highly toxic and linked to cancer, neurological disorders, and cardiovascular diseases. Tetracycline antibiotics, widely used to treat respiratory infections, can contaminate water through improper disposal, contributing to antibiotic resistance and other health hazards.
“Our sensor can detect Mercury and tetracyclines at extremely low concentrations,” said Prof. Kundu. “We synthesised carbon dots from low-cost, biogenic precursors, milk protein and thymine. Their nanoscale size and inherent fluorescence make this a highly sensitive and rapid detection technique. The sensor has potential applications not only in water testing but also in biological systems.”
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The sensor operates on a straightforward principle: carbon dots glow under ultraviolet (UV) light but dim in the presence of harmful substances such as Mercury or tetracyclines, providing an immediate visual signal of contamination. On laboratory testing, Mercury was detectable at 5.3 nanomolar (1.7 parts per billion), and tetracyclines at 10–13 nanomolar, well below safety thresholds set by the U.S. Environmental Protection Agency.
Tests were conducted across various samples, including tap and river water, milk, urine, and serum. For practical field use, the researchers also coated the sensor onto paper strips, enabling rapid detection with a simple UV lamp.
The research, co-authored by Prof. Kundu alongside scholars Ms. Pallabi Paul and Ms. Anushka Chakraborty, has been published in Microchimica Acta. The team emphasises that the technology remains at the laboratory stage and requires further validation before commercial deployment.
“With rising concerns over environmental pollutants and antibiotic residues, such a sensor can play a crucial role in safeguarding both human health and ecosystems,” Prof. Kundu added. “This is a step forward in developing accessible, real-time detection tools for harmful substances in water and other biological fluids.”
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