Absorbing molecules make both abdomen and back transparent in live mice

The field of tissue clearing has experienced rapid advancements in the past decades. Tissue clearing techniques primarily rely on physical or chemical approaches to match the refractive indices of cells and their surrounding medium, thereby reducing light scattering and rendering the tissue optically transparent. By doing so, it becomes possible to utilize fluorescence imaging and 3D reconstruction techniques to observe and analyze the contents and structures of tissues at a cellular level. However, effective research on in vivo tissue clearing remains limited due to the involvement of toxic substances and the removal of water or lipids. A recent article in Science reports a technique that achieves tissue transparency in live animals with absorbing molecules, marking a significant advancement in the field of in vivo tissue clearing. Although this work has great potential for imaging and light-based therapeutics, some labs found it difficult to reproduce the reported results. In this study, we report the successful reproduction of the findings, provide experimental details that we identified as key to reproducibility, present a new transparency effect observed in the back of live mice, which was not shown in the original paper, and offer insights into the future development and applications of in vivo clearing reagents.