Abstract In this review, we describe dielectric properties of biological tissues and liquids in the context of terahertz (THz) biophotonics. We discuss a model of the THz dielectric permittivity of water and water-containing media, which yields analysis of the relaxation and damped resonant molecules modes. We briefly describe modern techniques of THz spectroscopy and imaging employed in biophotonics with a strong emphasize on a THz time-domain spectroscopy. Furthermore, we consider the methods of sub-wavelength resolution THz imaging and the problem of THz wave delivery to hard to access tissues and internal organs. We consider the THz dielectric properties of biological solutions and liquids. Although strong absorption by water molecules prevents THz-waves from penetration of hydrated tissues and probing biological molecules in aqueous solutions, we discuss approaches for overcoming these drawbacks – novel techniques of freezing and temporal dehydration by application of hyperosmotic agents which have a potential for cancer detection. We review recent applications of THz technology in diagnosis of malignancies and aiding histology paying particular attention to the origin of contrast observed between healthy and pathological tissues. We consider recent applications of THz reflectometry in sensing the thinning dynamics of human pre-corneal tear film. Modern modalities of THz imaging, which relies on the concepts of multi-spectral and multi-temporal domains and employing the principles of color vision, phase analysis and tomography are discussed. Novel methods of THz spectra analysis based on machine learning, pattern recognition, chemical imaging and the revealing of the spatial distribution of various substances in a tissue, are analyzed. Advanced thermal model describing biological object irradiated by THz waves and phantoms mimicking the optical properties of tissues at THz frequencies are presented. Finally, application of the high-resolution THz spectroscopy in analytic chemistry, biology and medicine are described.

中文翻译：

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太赫兹生物光子学作为研究生物组织和液体的介电和光谱特性的工具

摘要 在这篇综述中，我们描述了太赫兹 (THz) 生物光子学背景下生物组织和液体的介电特性。我们讨论了水和含水介质的 THz 介电常数模型，该模型产生了弛豫和阻尼共振分子模式的分析。我们简要描述了生物光子学中采用的太赫兹光谱和成像的现代技术，并着重强调了太赫兹时域光谱学。此外，我们考虑了亚波长分辨率太赫兹成像的方法以及太赫兹波传输到难以接近的组织和内部器官的问题。我们考虑了生物溶液和液体的太赫兹介电特性。尽管水分子的强烈吸收阻止了太赫兹波穿透水合组织和探测水溶液中的生物分子，我们讨论了克服这些缺点的方法——通过应用具有癌症检测潜力的高渗剂进行冷冻和暂时脱水的新技术。我们回顾了 THz 技术在恶性肿瘤诊断和辅助组织学方面的最新应用，特别关注健康和病理组织之间观察到的对比度的起源。我们考虑了 THz 反射计在检测人类角膜前泪膜变薄动态方面的最新应用。讨论了依赖于多光谱和多时域概念并采用色觉、相位分析和断层扫描原理的太赫兹成像的现代模式。基于机器学习、模式识别、分析化学成像和揭示组织中各种物质的空间分布。介绍了描述由太赫兹波和模拟组织在太赫兹频率下的光学特性的幻影照射的生物对象的高级热模型。最后，描述了高分辨率太赫兹光谱在分析化学、生物学和医学中的应用。