New Method Developed to Measure Intracellular Water in Biological Systems

A new method to measure intracellular water in biological systems has been developed, offering a significant advancement in understanding cellular function and disease mechanisms. The technique enables live, spatially-resolved imaging of absolute intracellular water content, addressing a longstanding challenge in cell biology where most methods only report relative changes in water levels.

Researchers applied holotomography to quantify absolute intracellular water content in cells undergoing mitosis and in response to external stressors such as osmotic changes. This approach allows for detailed observation of how water distribution shifts during critical cellular processes, providing insights into homeostasis and stress response at the subcellular level.

The method builds on prior work using Raman micro-spectroscopy to study the structure of water in individual living cells. That research revealed that approximately 3% of intracellular water exhibits non-bulk-like properties, characterized by a weakened hydrogen-bonded network and more disordered tetrahedral structure. This population is attributed to biointerfacial water surrounding biomolecules, with modeling suggesting that soluble proteins are typically surrounded by about one molecular layer of such water.

By combining absolute quantification with structural insights, the new technique provides a more complete picture of intracellular water behavior. Researchers note that water regulates or governs a wide range of biological processes, including protein folding, enzyme catalysis, membrane self-assembly and substrate recognition, making precise measurement essential for understanding both normal function and disease states.

The development holds particular relevance for cancer research, where alterations in intracellular water dynamics have been linked to tumor progression and response to therapy. Ability to monitor these changes in real time could improve understanding of how cancer cells adapt to microenvironmental stresses and potentially inform new diagnostic or therapeutic strategies.

While the method represents a technical advance in biophysical imaging, its value lies in enabling fundamental research into the role of water in cellular physiology. By providing access to absolute, spatially resolved data in live cells, it supports investigations into how intracellular water contributes to health and disease across various cell types, and conditions.