Treweek Jennifer B, Chan Ken Y, Flytzanis Nicholas C, Yang Bin, Deverman Benjamin E, Greenbaum Alon, Lignell Antti, Xiao Cheng, Cai Long, Ladinsky Mark S, Bjorkman Pamela J, Fowlkes Charless C, Gradinaru Viviana
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA.
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA.
Nat Protoc. 2015 Nov;10(11):1860-1896. doi: 10.1038/nprot.2015.122. Epub 2015 Oct 22.
To facilitate fine-scale phenotyping of whole specimens, we describe here a set of tissue fixation-embedding, detergent-clearing and staining protocols that can be used to transform excised organs and whole organisms into optically transparent samples within 1-2 weeks without compromising their cellular architecture or endogenous fluorescence. PACT (passive CLARITY technique) and PARS (perfusion-assisted agent release in situ) use tissue-hydrogel hybrids to stabilize tissue biomolecules during selective lipid extraction, resulting in enhanced clearing efficiency and sample integrity. Furthermore, the macromolecule permeability of PACT- and PARS-processed tissue hybrids supports the diffusion of immunolabels throughout intact tissue, whereas RIMS (refractive index matching solution) grants high-resolution imaging at depth by further reducing light scattering in cleared and uncleared samples alike. These methods are adaptable to difficult-to-image tissues, such as bone (PACT-deCAL), and to magnified single-cell visualization (ePACT). Together, these protocols and solutions enable phenotyping of subcellular components and tracing cellular connectivity in intact biological networks.
为便于对整个标本进行精细表型分析,我们在此描述了一套组织固定-包埋、去污剂清除和染色方案,这些方案可用于在1-2周内将切除的器官和整个生物体转化为光学透明样本,同时不损害其细胞结构或内源性荧光。PACT(被动透明技术)和PARS(原位灌注辅助剂释放)在选择性脂质提取过程中使用组织-水凝胶杂种来稳定组织生物分子,从而提高清除效率和样本完整性。此外,经PACT和PARS处理的组织杂种的大分子通透性支持免疫标记物在整个完整组织中的扩散,而RIMS(折射率匹配溶液)通过进一步减少已清除和未清除样本中的光散射,实现深度高分辨率成像。这些方法适用于难以成像的组织,如骨骼(PACT-deCAL),也适用于放大的单细胞可视化(ePACT)。总之,这些方案和溶液能够对完整生物网络中的亚细胞成分进行表型分析,并追踪细胞连接性。