INST scientists develop glowing nanosensor for rapid nicotine, cotinine detection

he innovation could pave the way for early and low-cost screening of smoking exposure and second-hand smoke biomarkers

Scientists at Institute of Nano Science and Technology (INST), an autonomous institute under the Department of Science and Technology, have developed a tiny fluorescent “turn-on” sensor that can rapidly detect nicotine and its major metabolite, cotinine, in water-based media and living cells.

The innovation could pave the way for early and low-cost screening of smoking exposure and second-hand smoke biomarkers. 

Smoking and passive smoke exposure continue to pose serious global health risks. While nicotine is highly addictive and harmful, cotinine serves as a long-lasting and stable biomarker found in blood, saliva, and urine, making it a critical indicator for monitoring tobacco exposure.

The INST team designed the sensor using iron-based metal-organic framework (Fe-III-MOF) nanospheres—microscopic sponge-like porous structures made from iron. Synthesised through a solvothermal process, these nanospheres contain tiny pores capable of trapping nicotine and cotinine molecules. Once these molecules enter the pores, the nanospheres emit a brighter blue-shifted fluorescence signal, enabling rapid detection. 

Using intracellular imaging and confocal microscopy, researchers tracked cellular uptake and confirmed that the probe works effectively inside living cells. The study, published in Nanoscale, also found the nanospheres to be highly selective, recyclable, and biocompatible, with low cytotoxicity—making them suitable for biological and medical applications. 

Researchers said the fluorescence enhancement is driven by host–guest interactions and electron transfer, resulting in a stronger emission signal. Unlike conventional methods such as GC-MS, HPLC, electrophoresis, and immunoassays—which are expensive, time-consuming, and require skilled handling—the new sensor is simple to operate and works efficiently in aqueous environments.

Given the abundance and safety profile of iron, the Fe-based MOF platform could support future development of non-invasive health monitoring tools, affordable tobacco exposure screening kits, and next-generation fluorescent biosensors for other biomarkers. The innovation could have wide applications in public health surveillance, addiction research, and studies on nicotine metabolism.