近日，中国科学院植物研究所于龙江团队研究了近红外II窗口的体内钙成像。2025年12月24日，《美国化学会志》发表了这一成果。

由于传统钙离子（Ca²⁺）指示剂的激发与发射波长处于400–750 nm范围内，光线散射问题使得高灵敏度、高分辨率的活体哺乳动物深层组织无创钙成像面临挑战。

研究组通过发掘一种源自富碳酸钙环境细菌（嗜热着色菌）的天然蛋白，实现了超过1000 nm的近红外二区（NIR-II）钙成像。这种高光稳定性的荧光蛋白可在培养的哺乳动物细胞中对细胞内Ca²⁺响应刺激药物的过程进行NIR-II成像，其灵敏度与可见光区Ca²⁺指示剂相当。研究组成功以高灵敏度、高分辨率和高对比度实现了活体肿瘤内Ca²⁺瞬变响应两种不同治疗策略的NIR-II成像，为通过无创深层组织钙成像纵向评估治疗效果开辟了新途径。

附：英文原文

Title: In Vivo Calcium Imaging in the Near-Infrared II Window

Author: Danyang Xu, Zhisheng Wu, Hui Yang, Gu Chen, Wayne Jason Li, Xingyu Yue, Guang-Lei Wang, Sixin Xu, Hanze Yu, Yuanhua Liu, Zideng Dai, Haibo Jiang, Long-Jiang Yu, Hongjie Dai, Feifei Wang

Issue&Volume: December 24, 2025

Abstract: Noninvasive deep-tissue calcium imaging of live mammals with high sensitivity and resolution is challenging owing to light scattering experienced by traditional calcium ion (Ca2+) indicators with excitation and emission wavelengths within 400–750 nm. Here, we report near-infrared II (NIR-II) calcium imaging beyond 1000 nm by exploring a natural protein derived from a bacterium (Thermochromatium tepidum) living in a calcium carbonate-rich environment. This highly photostable fluorescent protein enables NIR-II imaging of intracellular Ca2+ responses to stimulant drugs in cultured mammalian cells with sensitivity comparable to that of visible Ca2+ indicators. We achieve in vivo NIR-II imaging of Ca2+ transients in response to two different tumor treatment strategies in intact tumors with high sensitivity, resolution, and contrast, opening the possibility of noninvasive deep-tissue calcium imaging for assessing treatment efficacy longitudinally.

DOI: 10.1021/jacs.5c13641

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c13641