Kanazawa University research: Scientists develop a new method to measure cellular energy in real time

KANAZAWA, Japan, Nov. 20, 2025 /PRNewswire/ -- Researchers at the Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, have developed a breakthrough method for quantitative imaging of ATP levels inside living cells. The study, published in Nature Communications, introduces qMaLioffG, a genetically encoded fluorescence lifetime indicator that allows scientists to observe how cells produce and consume energy in real time.

ATP (adenosine triphosphate) is the universal "fuel" for life, powering nearly every biological process. Measuring ATP levels accurately inside cells has long been a challenge: traditional fluorescent indicators often provide only rough estimates and are prone to errors from light intensity or imaging conditions. The new method solves these problems by relying on fluorescence lifetime—the time a fluorescent protein glows after pulsed excitation—rather than brightness. This makes the measurements more quantitative and reliable.

Experimental Approach

The team led by Satoshi Arai designed qMaLioffG by carefully engineering a fluorescent protein that behaves differently depending on how much ATP is present (Figure 1). When ATP binds to this protein, the duration of its glow—known as fluorescence lifetime—changes in a measurable way. Unlike brightness, which can be influenced by microscope settings, protein concentration, or cell shape, fluorescence lifetime is unaffected by experimental conditions and reflects the actual amount of ATP.

To test their design, the researchers introduced the qMaLioffG protein into a variety of living cells and tissues, including human skin cells, cancer cells, mouse embryonic stem cells, and even fruit fly brains (Figure 2). They then applied fluorescence lifetime imaging microscopy (FLIM), an advanced form of microscopy that captures these subtle lifetime shifts. By recording these changes in real time, the team created accurate maps of ATP levels across cells and tissues, showing where and how energy is used.

This approach marks a major advance over older methods, which could only provide relative changes in brightness and were prone to errors from lighting or imaging conditions. With qMaLioffG, researchers can now perform true quantitative imaging of ATP, opening new opportunities to study how energy metabolism drives health and disease.

Key Findings

• qMaLioffG provides reliable, quantitative imaging of ATP in living cells.
• The method works in diverse systems, from patient-derived fibroblasts to cancer cells, stem cells, and fruit fly brains.
• It reveals subtle differences in energy use across different tissues and disease models.

"This is the first time we can perform true quantitative imaging of ATP levels inside living cells in real time," says Arai. "It opens up exciting opportunities to understand energy metabolism in conditions like cancer, neurodegenerative diseases, and stem cell biology."

Potential Impact

This new method is expected to accelerate research in energy metabolism, regenerative medicine, and disease mechanisms. Because it works with standard 488 nm laser systems already common in many labs, it will be widely accessible to researchers worldwide.

Future Research

Although qMaLioffG represents a significant leap forward, several challenges remain. The current study focused on cultured cells, model organisms, and tissue-like spheroids; applying the method to whole living organisms and ultimately human tissues will be the next step. Researchers also need to explore how qMaLioffG performs in long-term imaging, since energy metabolism is highly dynamic and can fluctuate over hours or days.

Future directions include:

• Clinical validation, adapting qMaLioffG for use in patient-derived samples to study diseases such as cancer, diabetes, and neurodegeneration.
• Integration with other imaging methods, combining ATP mapping with calcium or pH sensors to understand how energy connects with cell signaling.
• Drug discovery applications, using the method to test how new compounds affect cellular energy balance.

By advancing toward real-time, quantitative imaging of energy in living tissues, the Kanazawa team aims to provide a platform that could transform biomedical research and support the development of new therapies.

Glossary

• ATP (adenosine triphosphate) – The molecule that stores and transfers energy in cells.
• Quantitative imaging – A method that provides precise numerical values, not just relative changes.
• Fluorescence lifetime imaging microscopy (FLIM) – An imaging approach that measures how long a fluorescent molecule glows, independent of brightness.

Figures

Figure 1: https://nanolsi.kanazawa-u.ac.jp/wp/wp-content/uploads/Fig.1en_Nat.-Commun._Nov.2025.jpg

Caption: qMaLioffG is an ATP indicator that converts ATP concentration into fluorescence lifetime. Using a calibration curve (fluorescence lifetime vs. ATP concentration), we calculated fluorescence lifetime values for each pixel and obtained quantitative ATP concentration information. We then performed quantitative analysis of ATP levels in cells with impaired ATP-producing capacity due to mitochondrial disease (Figures modified from the published article with permission from the publisher).

Figure 2: https://nanolsi.kanazawa-u.ac.jp/wp/wp-content/uploads/Fig.2en_Nat.-Commun._Nov.2025.jpg

Caption: ATP mapping of Drosophila brain (Figures modified from the published article with permission from the publisher).

Reference

Satoshi Arai*, Hideki Itoh, Cong Quang Vu, Loan Thi Ngoc Nguyen, Mizuho Nakayama, Masanobu Oshima, Atsuya Morita, Kazuko Okamoto, Satoru Okuda, Aki Teranishi, Madori Osawa, Yoshiteru Tamura, Shigeaki Nonoyama, Megumi Takuma, Toshinori Fujie, Satya Ranjan Sarker, Thankiah Sudhaharan, Akihiro Furube, Tetsuro Katayama, Taketoshi Kiya, E. Birgitte Lane, and Tetsuya Kitaguchi*. "qMaLioffG: a genetically encoded green fluorescence lifetime-based indicator enabling quantitative imaging of intracellular ATP." Nature Communications 16, Article number: 9972 (2025).

Published: 13 November 2025

DOI: 10.1038/s41467-025-64946-2

URL: https://www.nature.com/articles/s41467-025-64946-2

Funding and acknowledgments

This research was supported by the World Premier International Research Center Initiative (WPI), the Japan Society for the Promotion of Science (JSPS), the Ministry of Education, Culture, Sports, Science and Technology (MEXT), JST FOREST Program, the Nakatani Foundation, A*STAR Singapore, the Human Frontier Science Program, and other international programs.

Contact

Kimiko Nakazaki (Ms)
Project Planning and Outreach, NanoLSI Administration Office
Nano Life Science Institute, Kanazawa University
Kakuma-machi, Kanazawa 920-1192, Japan
Email: nanolsi-office@adm.kanazawa-u.ac.jp

About Nano Life Science Institute (WPI-NanoLSI), Kanazawa University

Understanding nanoscale mechanisms of life phenomena by exploring "uncharted nano-realms".

Cells are the basic units of almost all life forms. We are developing nanoprobe technologies that allow direct imaging, analysis, and manipulation of the behavior and dynamics of important macromolecules in living organisms, such as proteins and nucleic acids, at the surface and interior of cells. We aim at acquiring a fundamental understanding of the various life phenomena at the nanoscale.

https://nanolsi.kanazawa-u.ac.jp/en/

About the World Premier International Research Center Initiative (WPI)

The WPI program was launched in 2007 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).

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About Kanazawa University

Founded in 1862 in Ishikawa Prefecture, Kanazawa University is one of Japan's leading comprehensive national universities with a history spanning more than 160 years. With campuses at Kakuma and Takaramachi–Tsuruma, the university upholds its guiding principle of being "a research university dedicated to education, while opening its doors to both local and global society."

Internationally recognized for its research institutes, including the Nano Life Science Institute (WPI-NanoLSI) and the Cancer Research Institute, Kanazawa University promotes interdisciplinary research and global collaboration, driving progress in health, sustainability, and culture.

http://www.kanazawa-u.ac.jp/en/