近日，美国波士顿大学的Ji-Xin Cheng及其研究团队取得一项新进展。经过不懈努力，他们利用短波红外光热显微镜实现毫米深微米分辨率振动成像。相关研究成果已于2024年6月25日在国际知名学术期刊《自然—光子学》上发表。

该研究团队提出了一种短波红外光热(SWIP)显微镜，用于毫米深的振动成像，其具有微米的横向分辨率。通过泵浦碳氢键的泛频跃迁，并用短波红外光探测随后的光热透镜，SWIP可以获得位于高散射模体中800微米深度的1微米聚合物颗粒的化学对比度。SWIP信号的振幅比光声探测信号的振幅大63倍。

研究人员进一步证明SWIP技术在完整的肿瘤球体以及厚实的肝、皮肤、脑和乳腺组织层状结构中分解细胞内脂质的能力。SWIP显微镜填补了亚细胞分辨率和毫米级穿透的振动成像空白，预示着生命科学和临床应用的广阔潜力。

据悉，深层组织化学成像在生物和医学应用中具有至关重要的作用。目前的方法受到水分吸收和组织散射的影响，这将成像深度限制在数百微米。短波红外光谱窗口允许深层组织成像，但通常具有令人不满意的空间分辨率或低检测灵敏度。

附：英文原文

Title: Millimetre-deep micrometre-resolution vibrational imaging by shortwave infrared photothermal microscopy

Author: Ni, Hongli, Yuan, Yuhao, Li, Mingsheng, Zhu, Yifan, Ge, Xiaowei, Yin, Jiaze, Dessai, Chinmayee Prabhu, Wang, Le, Cheng, Ji-Xin

Issue&Volume: 2024-06-25

Abstract: Deep tissue chemical imaging has a vital role in biological and medical applications. Current approaches suffer from water absorption and tissue scattering, which limits imaging depth to hundreds of micrometres. The shortwave infrared spectral window allows deep tissue imaging but typically features unsatisfactory spatial resolution or low detection sensitivity. Here we present a shortwave infrared photothermal (SWIP) microscope for millimetre-deep vibrational imaging with micrometre lateral resolution. By pumping the overtone transition of carbon–hydrogen bonds and probing the subsequent photothermal lens with shortwave infrared light, SWIP can obtain chemical contrast from 1μm polymer particles located at 800μm depth in a highly scattering phantom. The amplitude of the SWIP signal is shown to be 63 times larger than that of the optically probed photoacoustic signal. We further demonstrate that SWIP can resolve intracellular lipids across an intact tumour spheroid and the layered structure in thick liver, skin, brain and breast tissues. SWIP microscopy fills a gap in vibrational imaging with subcellular resolution and millimetre-level penetration, which heralds broad potential for life science and clinical applications.

DOI: 10.1038/s41566-024-01463-6

Source: https://www.nature.com/articles/s41566-024-01463-6