A new paper titled “Fine visualization of biological cells using X-ray micro-CT with the slow freezing contrast improved method” was published in Scientific Reports on July 29, 2025.
https://doi.org/10.1038/s41598-025-09070-3

In this study, we utilized the natural aggregation of solutes (such as sugars) that occurs when fruits are slowly frozen. This innovative approach allows for high-sensitivity, non-destructive, 3D imaging of biological cells without the need for contrast agents. Thanks to this method, it is now possible to clearly visualize the internal cells of fruits—such as melons, grapes, and mandarins—that were previously difficult to observe.

We also demonstrated that the stripe patterns formed during this process depend on the concentration of solutes, making it possible to measure the sugar content of individual cells! Furthermore, we showed that even in animal tissues fixed with formalin, fine structures can be visualized without contrast agents due to the aggregation of formaldehyde.

Since this contrast enhancement can be achieved simply by combining conventional X-ray CT with slow freezing (cryotechniques), the method is expected to see widespread use and development in the future.