2025-08-24 大阪大学
図1. (上)本研究成果の技術のコンセプト。(下)蛍光顕微鏡で観察中のラット初代培養心筋細胞内を伝搬するCa²⁺波を急速凍結固定。細胞にはCa²⁺濃度が高くなると明るく光る蛍光性Ca²⁺指示薬を導入。細胞の左上から右下に流れるCa²⁺波が急速凍結により瞬時に停止し、凍結直前の細胞内Ca²⁺分布が保持されている様子が確認できる。
<関連情報>
- https://resou.osaka-u.ac.jp/ja/research/2025/20250824_1
- https://www.nature.com/articles/s41377-025-01941-8
時間決定論的クライオ光学顕微鏡 Time-deterministic cryo-optical microscopy
Kosuke Tsuji,Masahito Yamanaka,Yasuaki Kumamoto,Shoko Tamura,Wakana Miyamura,Toshiki Kubo,Kenta Mizushima,Kakeru Kono,Hanae Hirano,Momoko Shiozaki,Xiaowei Zhao,Heqi Xi,Kazunori Sugiura,Shun-ichi Fukushima,Takumi Kunimoto,Yoshino Tanabe,Kentaro Nishida,Kentaro Mochizuki,Yoshinori Harada,Nicholas I. Smith,Rainer Heintzmann,Zhiheng Yu,Meng C. Wang,Takeharu Nagai,… Katsumasa Fujita
Nature Science & Applications Published:23 August 2025
DOI:https://doi.org/10.1038/s41377-025-01941-8
Abstract
Fluorescence microscopy enables the visualization of cellular morphology, molecular distribution, ion distribution, and their dynamic behaviors during biological processes. Enhancing the signal-to-noise ratio (SNR) in fluorescence imaging improves the quantification accuracy and spatial resolution; however, achieving high SNR at fast image acquisition rates, which is often required to observe cellular dynamics, still remains a challenge. In this study, we developed a technique to rapidly freeze biological cells in milliseconds during optical microscopy observation. Compared to chemical fixation, rapid freezing provides rapid immobilization of samples while more effectively preserving the morphology and conditions of cells. This technique combines the advantages of both live-cell and cryofixation microscopy, i.e., temporal dynamics and high SNR snapshots of selected moments, and is demonstrated by fluorescence and Raman microscopy with high spatial resolution and quantification under low temperature conditions. Furthermore, we also demonstrated that intracellular calcium dynamics can be frozen rapidly and visualized using fluorescent ion indicators, suggesting that ion distribution and conformation of the probe molecules can be fixed both spatially and temporally. These results confirmed that our technique can time-deterministically suspend and visualize cellular dynamics while preserving molecular and ionic states, indicating the potential to provide detailed insights into sample dynamics with improved spatial resolution and temporal accuracy in observations.
