Researchers from the University of Bath have developed fluorescent molecular probes that can detect changes in glucose levels inside living animals, giving scientists new ways of visualising sugar uptake, studying diabetes, cancer and other metabolic diseases in whole organisms in real time.
Seeing sugars in action
Carbohydrates such as glucose play essential roles in energy metabolism and diabetes, yet monitoring them inside living tissues remains a major scientific challenge.
The interdisciplinary team designed fluorescent molecular probes that combine chemicals called boronic acids, which selectively bind to sugars, with advanced imaging technologies capable of visualising molecular behaviour inside living systems.
The probes were able to detect changes in glucose levels in both cultured cells and living zebrafish.
"Our work demonstrates that synthetic carbohydrate-recognising probes can monitor glucose-related processes in living organisms in real time," said Professor Sofia I. Pascu, from the University’s Department of Chemistry and one of the study's corresponding authors. "This represents an important step towards next-generation tools for investigating metabolic disorders and developing precision diagnostic technologies."
The researchers combined the probes with cutting-edge multiphoton fluorescence lifetime imaging microscopy (MP-FLIM), an advanced technique that measures subtle changes in lifetime (how long a fluorescence signal lasts), instead of simply measuring brightness. This approach enabled the team to visually map which cells absorb and use sugars in real time within a living system.
Detecting elevated glucose in living systems
To test whether the technology could work in vivo, the team used zebrafish, a widely used model organism for metabolic research.
Several probes accumulated strongly in the digestive system of zebrafish larvae, where their fluorescence changed in response to external glucose challenge.
They also used the same approach to successfully distinguish insulin-deficient zebrafish carrying a diabetes-like mutation from healthy siblings.
The diabetic fish showed significantly reduced fluorescence due to their elevated glucose levels, demonstrating the probe's ability to detect glucose changes within a living vertebrate organism.
Dr David Gurevich, corresponding author and Sir Henry Dale Wellcome Trust Research Fellow in the University’s Department of Life Sciences, said: "Our results show that synthetic boronic acid-based fluorescent probes can report on glucose fluctuations caused by both external sugar exposure and in an insulin-deficient living organism.
"This could give researchers a new way to connect changes in glucose with the biological effects of metabolic and other diseases."
Future Applications in Diabetes and Cancer
Beyond glucose monitoring, the researchers believe the platform could be adapted to detect other biologically important carbohydrates and metabolic markers. Since abnormal carbohydrate metabolism is a hallmark of diseases including diabetes and many cancers, the technology could ultimately support earlier diagnosis, drug discovery and personalised treatment strategies.
Co-corresponding author Professor Tony D. James added: "By bringing together supramolecular chemistry, advanced photonics, and biological models, we have created a versatile platform for imaging metabolic processes in real time.
“This work demonstrates the power of combining chemistry, biology and advanced imaging to gain new insights into living systems. We are now exploring how these technologies might be developed further for theranostic applications and future drug-screening tools."
International Collaboration and Scientific Achievement
The research reflects a highly interdisciplinary and international collaboration involving biologists, physicists and chemists from the University of Bath, University of Birmingham, Universidad Autónoma de Madrid, the Spanish National Research Council (CSIC), and STFC Rutherford Appleton Laboratory.
The team included the late Professor John S. Fossey of the University of Birmingham, who was a leading figure in boronic acid chemistry and molecular recognition; his insight and collaboration helped shape this project and many related studies.
The publication, in the journal Advanced Science, stands as a tribute to his scientific legacy and enduring impact on colleagues, students and collaborators across the field.