Clarity and Immunofluorescence on Mouse Brain Tissue

Tissue optical clearing techniques have provided essential tools for visualization of neural networks in unsectioned brain tissue. Here, we describe a passive optical clearing method based on hydrogel embedding, PACT (passive clarity technique), which is relatively simple. Advantages of PACT include tissue transparency, fluorescence preservation, and immunostaining compatibility for obtaining three-dimensional structures of mouse brain tissue. Additionally, it can enhance the penetration of antibodies in immunostaining and allows efficient immunolabeling of large volumes. After clearing with PACT, one can achieve high-resolution imaging in deep tissue at the millimeter-scale level with optical imaging microscopy. © 2018 by John Wiley & Sons, Inc.