Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Adv Mater. 2023 Jul;35(28):e2301208. doi: 10.1002/adma.202301208. Epub 2023 May 28.
Label-free and nondestructive mid-infrared vibrational hyperspectral imaging is an essential tissue analysis tool, providing spatially resolved biochemical information critical to understanding physiological and pathological processes. However, the chemically complex and spatially heterogeneous composition of tissue specimens and the inherently weak interaction of infrared light with biomolecules limit the analytical performance of infrared absorption spectroscopy. Here, an advanced mid-infrared spectrochemical tissue imaging modality is introduced using metasurfaces that support strong surface-localized electromagnetic fields to capture quantitative molecular maps of large-area murine brain tissue sections. The approach leverages polarization-multiplexed multi-resonance plasmonic metasurfaces to simultaneously detect various functional biomolecules. The surface-enhanced mid-infrared spectral imaging method eliminates the non-specific effects of bulk tissue morphology on quantitative spectral analysis and improves chemical selectivity. This study shows that metasurface enhancement increases the retrieval of amide I and II bands associated with protein secondary structures. Moreover, it is demonstrated that plasmonic metasurfaces enhance the chemical contrast in infrared images and enable detection of ultrathin tissue regions that are not otherwise visible to conventional mid-infrared spectral imaging. While this work uses murine brain tissue sections, the chemical imaging method is well-suited for other tissue types, which broadens its potential impact for translational research and clinical histopathology.
无标记和非破坏性的中红外振动高光谱成像是一种重要的组织分析工具，提供了对生理和病理过程至关重要的空间分辨生物化学信息。然而，组织标本的化学成分复杂且空间不均匀，以及红外光与生物分子的固有弱相互作用限制了红外吸收光谱的分析性能。在这里，我们介绍了一种使用亚表面的先进的中红外光谱化学组织成像模式，该模式支持强表面局域电磁场，以捕获大面积鼠脑组织切片的定量分子图谱。该方法利用偏振复用多共振等离子体亚表面同时检测各种功能生物分子。表面增强中红外光谱成像方法消除了体组织形态对定量光谱分析的非特异性影响，并提高了化学选择性。本研究表明，亚表面增强增加了与蛋白质二级结构相关的酰胺 I 和 II 带的提取。此外，还证明了等离子体亚表面增强了红外图像中的化学对比度，并能够检测到常规中红外光谱成像无法检测到的超薄组织区域。虽然这项工作使用了鼠脑组织切片，但化学成像方法非常适合其他组织类型，这扩大了其在转化研究和临床组织病理学中的潜在影响。
