Shabbir Muhammad Waqas, Asante-Asare David, Phillips Matthew, Ou Zihao
Department of Physics, The University of Texas at Dallas.
Department of Electrical and Computer Engineering, The University of Texas at Dallas.
J Vis Exp. 2025 Jul 11(221). doi: 10.3791/68629.
Dynamic imaging is a foundational tool in biology and medicine, but it is limited by light scattering in live tissues caused by refractive index mismatches, which reduces penetration depth and resolution in biological tissues. Previous work introduced a novel approach to achieve optical transparency in live animals by utilizing strongly absorbing molecules. When these absorbing molecules, such as Tartrazine, an FDA-approved dye commonly used in foods, dissolve in water, they modify the refractive index of the aqueous medium through Kramers-Kronig relations. This modulation allows reduction of the refractive index mismatch between separate components in tissue with distinct refractive indices, thus mitigating scattering. This article reports the detailed methodology of the tissue clearing technique using a Tartrazine-based aqueous solution, applied to both ex vivo and in vivo samples. This approach reversibly renders live mouse bodies transparent in the visible spectrum, enabling clearer and deeper imaging of internal processes and structures. An advanced image processing algorithm was then used to improve the contrast and segmentation of organs of interest. Additionally, high transparency in ex vivo samples, such as chicken breast, treated with Tartrazine-based solution, is shown. This method offers a versatile and accessible approach to enhance imaging capabilities across various modalities and paves the way for advancement in the understanding of complex biological systems.
动态成像在生物学和医学中是一种基础工具，但它受到活组织中由折射率不匹配引起的光散射的限制，这降低了生物组织中的穿透深度和分辨率。先前的工作引入了一种利用强吸收分子在活体动物中实现光学透明的新方法。当这些吸收分子，如柠檬黄（一种美国食品药品监督管理局批准的常用于食品的染料）溶解于水时，它们通过克拉默斯-克勒尼希关系改变水介质的折射率。这种调制使得具有不同折射率的组织中各独立成分之间的折射率不匹配得以减小，从而减轻散射。本文报道了使用基于柠檬黄的水溶液的组织透明化技术的详细方法，该方法应用于离体和活体样本。这种方法在可见光谱中可逆地使活体小鼠身体变得透明，能够更清晰、更深入地对内部过程和结构进行成像。然后使用一种先进的图像处理算法来提高感兴趣器官的对比度和分割效果。此外，还展示了用基于柠檬黄的溶液处理过的离体样本（如鸡胸肉）具有高透明度。这种方法提供了一种通用且易于使用的途径来增强各种成像方式的成像能力，并为深入理解复杂生物系统铺平了道路。
