Daijiworld Media Network - New Delhi

New Delhi, Jun 30: In a breakthrough that could revolutionize cancer diagnostics, researchers at the Indian Institute of Science (IISc) have developed a simple, cost-effective sensor capable of rapidly detecting liver cancer and other diseases by targeting a key enzyme biomarker.

The innovation hinges on the use of terbium, a rare earth metal known for its distinctive luminescent properties. The research team engineered a unique terbium-based probe that can detect the presence of beta-glucuronidase — an enzyme linked to liver cancer as well as colon, breast, and renal cancers, in addition to infections like UTIs and AIDS.

Beta-glucuronidase is typically involved in breaking down glucuronic acid, but elevated levels in the body are associated with various pathological conditions. Detecting it accurately and affordably can, therefore, provide a valuable early warning signal.

Unlike conventional fluorescence and colorimetry-based methods that often struggle with background noise and sensitivity, the IISc sensor leverages terbium’s long-lived excited states to eliminate short-lived background interference, resulting in a clearer and more precise signal. “The ability of rare earth metals to have long-lived excited states allows us to filter out short-lived background fluorescence,” explained Ananya Biswas, co-author of the study published in the journal Chemistry.

The project took off through investigations into the gel-forming properties of metal ions. The researchers discovered that terbium ions embedded within a gel matrix derived from bile salts emitted a distinct green fluorescence. They then introduced a molecule called 2,3-Dihydroxynaphthalene (2,3-DHN), which was chemically masked using glucuronic acid. In the presence of beta-glucuronidase, the glucuronic acid mask is cleaved, allowing the 2,3-DHN to act as an “antenna” that absorbs UV light and transfers energy to the terbium ions, dramatically amplifying the glow.

To ensure the solution could be widely used, especially in resource-constrained settings, the team embedded the sensor into paper discs. These discs, when exposed to a sample containing beta-glucuronidase, emitted a bright green glow under UV light. The glow could be easily analysed using a UV lamp and ImageJ, a free open-source image processing software.

Notably, the sensor was able to detect enzyme concentrations significantly below the levels typically observed in cirrhosis — a late-stage liver disease — underscoring its potential for early-stage diagnosis.

While the innovation still awaits further clinical validation, researchers are optimistic. The affordability and simplicity of the sensor may enable widespread screening for liver and other cancers, and make routine biomarker detection more accessible — particularly in rural and underfunded healthcare systems.