In biomedical research, seeing is believing. Deciphering the structural complexity of human organs has always been a major challenge due to the lack of technologies to image them at the cellular level. Recent developments in tissue clearing allowed researchers to obtain first cellular views of intact transparent mouse organs in 3D. These methods, however, were not applicable to human organs.
“We had to change our approach completely”
Human organs are particularly stiff due to accumulation of insoluble molecules including collagen in tissues that have grown for years or even decades. Thus, traditional detergents that are used for making mouse organs transparent do not work on human organs, particularly adult ones. “We had to change our approach completely and start from scratch to find new chemicals which can make human organs transparent,” says Shan Zhao, PhD student at Helmholtz Zentrum München and first author of the study. After exhausting trials, the team discovered that a detergent called CHAPS could make small holes throughout the entire stiff human organs. CHAPS allows additional solutions to travel deep into centimeters-thick human organs and convert them into a transparent structure.