New Delhi, Sep 1 (IANS) — Researchers at the Indian Institute of Technology (IIT) Guwahati have created an innovative nanosensor made from milk protein and thymine that can rapidly detect mercury and antibiotic contaminants in water—substances linked to cancer risk.
With increasing urbanization, industrialization, and pharmaceutical use, water pollution has become a critical global concern, threatening ecosystems and human health.
The newly developed sensor utilizes carbon dots—tiny particles just a few billionths of a meter in size—that fluoresce under ultraviolet light. When harmful pollutants like mercury or tetracycline antibiotics are present, the fluorescence dims, providing a quick and visible indication of contamination even at very low levels.
“Detecting pollutants such as mercury and antibiotics is crucial not only in water but also in biological fluids. Mercury is highly carcinogenic, and excessive antibiotics pose serious health risks. Our sensor can detect mercury and tetracyclines at extremely low concentrations,” explained Prof. Lal Mohan Kundu from IIT Guwahati’s Department of Chemistry.
Tetracyclines, commonly used to treat respiratory infections, can contaminate water if improperly disposed of, leading to antibiotic resistance and other health hazards. Mercury, especially in its organic form, is linked to cancer, neurological disorders, and cardiovascular diseases.
The research, published in the journal Microchimica Acta, describes synthesizing carbon dots from cost-effective, biogenic precursors—milk protein and thymine, a nucleobase. The sensor’s nanoscale size and inherent fluorescence make it highly sensitive.
In laboratory tests, the sensor showed a measurable decrease in fluorescence within 10 seconds of exposure to contaminants. It can detect mercury at concentrations as low as 5.3 nanomolar (1.7 parts per billion), below the US Environmental Protection Agency’s safety limits, and tetracycline antibiotics at 10^-13 nanomolar.
To demonstrate versatility, the sensor was tested in various samples including tap and river water, milk, urine, and serum. For practical use, the team developed paper strips coated with the sensor, enabling quick, on-site detection of water contamination using a UV lamp.
This novel sensor offers a low-cost, highly accurate alternative to traditional water testing methods. Its biocompatibility also suggests potential applications in biomedical fields, though further validation is needed before commercial deployment, the researchers noted.
