The recent advent of tissue clearing techniques provides vast opportunities for volumetric three-dimensional (3D) imaging and analysis of biological specimens. While most major tissue clearing protocols were initially developed for applications to small rodent organs (particularly for the brain), a wide range of researchers has been tested various samples, including hard tissues, cultured spheroids and organoids, insects, or human tissues. 

This Methods Collection aims to introduce such user-driven ingenious attempts at extending tissue clearing technologies to the research community. For example, the expected articles participating in this Collection will cover:

• examples of clearing conditions for a specific biological sample (e.g., tissue other than the brain, samples from non-mammal species, or cultured spheroid/organoid)
• examples of 3D imaging (e.g., way of sample handling, a preparation method for imaging, and microscopy setup) 
• examples of image analysis for acquired 3D data

These articles are expected to describe specific tips for clearing, 3D imaging, and 3D image analysis, gleaned from the authors' trials and experiences.

Sharing these cutting-edge applications with a detailed protocol help to further facilitate the usage of tissue clearing technology, promoting a deeper understanding of biological systems.