Fig. 1. Overview of tissue optical clearing and imaging methods

Fig. 2. Two strategies for tissue optical clearing methods: reduction of light scattering and light absorption^[3]

Fig. 3. Overview of the main steps of tissue optical clearing methods^[32]. (a) Main steps of organic solvent-based clearing methods; (b) main steps of hydrophilic reagent-based clearing methods

Fig. 4. Classification of tissue optical clearing methods for imaging whole organs

Fig. 5. Clearing performance of different optical clearing methods^{[34-35,39,50,52,59,76,80,89]}

Fig. 6. Strategies for whole-mount immunolabeling of large tissues^[52,104]

Fig. 7. Several typical optical microimaging technologies for 3D imaging of large samples^[81,117]

Fig. 8. 3D reconstruction of whole organs by combining tissue clearing and optical imaging techniques^{[35,55,72,118]}