Experimental Solid State Group, Department of Physics, Imperial College London, London, UK.
Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK.
Commun Biol. 2023 May 31;6(1):583. doi: 10.1038/s42003-023-04943-7.
The ability to image cell chemistry at the nanoscale is key for understanding cell biology, but many optical microscopies are restricted by the (200-250)nm diffraction limit. Electron microscopy and super-resolution fluorescence techniques beat this limit, but rely on staining and specialised labelling to generate image contrast. It is challenging, therefore, to obtain information about the functional chemistry of intracellular components. Here we demonstrate a technique for intracellular label-free chemical mapping with nanoscale (30 nm) resolution. We use a probe-based optical microscope illuminated with a mid-infrared laser whose wavelengths excite vibrational modes of functional groups occurring within biological molecules. As a demonstration, we chemically map intracellular structures in human multiple myeloma cells and compare the morphologies with electron micrographs of the same cell line. We also demonstrate label-free mapping at wavelengths chosen to target the chemical signatures of proteins and nucleic acids, in a way that can be used to identify biochemical markers in the study of disease and pharmacology.
在纳米尺度上成像细胞化学的能力对于理解细胞生物学至关重要，但许多光学显微镜受到(200-250)nm 衍射极限的限制。电子显微镜和超分辨率荧光技术突破了这一限制，但依赖于染色和专门的标记来产生图像对比度。因此，很难获得关于细胞内成分功能化学的信息。在这里，我们展示了一种具有纳米级(30nm)分辨率的细胞内无标记化学映射技术。我们使用一种基于探针的光学显微镜，用中红外激光照明，其波长激发生物分子内功能基团的振动模式。作为演示，我们对人多发性骨髓瘤细胞中的细胞内结构进行了化学映射，并将形态与同一细胞系的电子显微镜图像进行了比较。我们还展示了在选择的波长下进行无标记映射，这些波长可靶向蛋白质和核酸的化学特征，可用于在疾病和药理学研究中识别生物化学标志物。
