Researchers at the University of Tokyo have developed a microscope capable of recording three-dimensional videos of chemical components inside living cells. The technology uses mid-infrared photothermal microscopy and can capture 19.2 three-dimensional image volumes every second, offering a way to observe chemical activity inside cells as it changes over time.
The research was announced by the university on October 30, 2026. The team said it accelerated conventional three-dimensional measurements by approximately 400 times, allowing researchers to track the movement of lipid droplets inside living cells using chemical signals associated with lipids.
The development could provide researchers with a more detailed view of how the internal structures of cells move and interact. It may also help scientists investigate the relationship between a cell’s chemical composition and its changing physical behaviour.
The findings were published in Nature Communications under the title “Video-rate volumetric chemical imaging via mid-infrared photothermal optical diffraction tomography.”
Why imaging living cells is challenging
Living cells are dynamic systems. Their internal components move, change shape and interact with one another. Some of these processes occur quickly, making it difficult to understand them using imaging techniques that capture only occasional snapshots.
Traditional microscopy can reveal the structure of cells, but researchers may need additional methods to identify the chemical composition of specific components. Fluorescent labels are used in many imaging techniques to highlight selected structures or molecules.
However, label-free imaging methods are also valuable. They can allow researchers to observe chemical information without attaching fluorescent markers or other labels to the material being studied.
The University of Tokyo team worked on improving mid-infrared photothermal microscopy, a technique that uses the interaction between infrared light and molecular vibrations to obtain chemical information.
The challenge has been to capture this information in three dimensions at a speed suitable for recording movement inside living cells.
How the new microscope works
Mid-infrared photothermal microscopy detects changes in a material caused by the absorption of mid-infrared light.
Molecules absorb light at frequencies associated with their vibrational properties. These absorption patterns provide information about chemical composition.
In the method described by the researchers, the absorption of mid-infrared light produces photothermal effects that can be detected through changes in refractive index using visible light.
This allows the microscope to visualise chemical components without relying on conventional molecular labels.
The research team combined this approach with optical diffraction tomography to produce volumetric images. Instead of recording only a flat two-dimensional image, the system reconstructs information across three dimensions.
The result is a microscope capable of recording a sequence of 3D chemical images at video rate.
Capturing 19.2 three-dimensional volumes every second
One of the key figures reported by the researchers is a capture rate of 19.2 volumes per second.
A volume is a three-dimensional image of the observed sample. At this rate, the system can produce almost 20 complete 3D chemical images every second.
The university said this represents an approximately 400-fold acceleration compared with conventional three-dimensional measurements.
The faster imaging allowed the team to track lipid droplets inside living cells. Lipid droplets are structures involved in storing fats and other lipids, and their movement can provide information about cellular activity.
By using lipid-specific signals, the researchers were able to follow the droplets in three dimensions and quantitatively analyse their motion.
This is an important difference from simply capturing a still image. Tracking movement over time can help researchers understand how cellular components behave within the wider environment of a living cell.
Spectroscopic imaging adds chemical detail
The researchers also demonstrated spectroscopic imaging at approximately 20 distinct wavenumbers within one second.
A wavenumber is a way of expressing the frequency of light, commonly used in infrared spectroscopy. Different molecular bonds and chemical groups absorb light at characteristic frequencies.
Collecting information across multiple wavenumbers can therefore provide more detailed chemical information than imaging at a single frequency.
The team’s demonstration suggests that the microscope can combine rapid three-dimensional imaging with the ability to examine chemical signatures at several infrared frequencies.
The university said the development establishes a new approach for investigating the relationship between intracellular dynamics and chemical composition in three dimensions.
Potential applications in biological research
The ability to observe chemical components moving inside living cells could be useful across several areas of biological research.
Researchers studying cell metabolism may be interested in how lipid droplets form, move and interact with other cellular structures. Scientists investigating cellular stress or disease-related changes may also want to observe how chemical components behave over time.
A three-dimensional view can provide information that is difficult to obtain from a single two-dimensional image. It can help researchers follow the movement of structures through different depths of a cell rather than observing only their projected position.
The technology may also be useful for studying processes where chemical composition and physical movement are closely linked.
These are potential research applications, not established clinical uses. The announcement does not claim that the microscope is ready for routine medical diagnosis or that it has already improved patient treatment.
Further work will be needed to understand its performance across different cell types, biological samples and experimental conditions.
What makes the development important
The new microscope addresses two connected challenges: chemical specificity and imaging speed.
A technique that reveals chemical composition but captures images too slowly may miss important changes in a living cell. A fast imaging system that provides limited chemical information may not tell researchers exactly what they are observing.
By combining label-free chemical imaging with rapid three-dimensional capture, the researchers aim to address both problems.
The reported rate of 19.2 volumes per second is a technical milestone, but the practical value of the system will depend on how reliably it can be used across different research settings.
The team will also need to demonstrate how the method performs with more complex biological samples and whether it can be integrated into established laboratory workflows.
The next stage of cellular imaging
The development adds to continuing efforts to make microscopy more informative, faster and less invasive.
As imaging technology improves, researchers can increasingly observe living biological systems rather than relying entirely on fixed samples or isolated snapshots. Chemical imaging provides another layer of information by helping scientists understand what structures are made of, not only where they are located.
The University of Tokyo’s work offers a promising tool for studying cell behaviour in three dimensions. Its ability to capture rapid chemical changes may help researchers investigate processes that were previously difficult to observe in real time.
The next question is how widely the technique can be applied and what new biological insights it will help reveal.