I Can See Clearly Now!

Abstract

An important challenge in microscopy is the development of high-resolution light microscopy methods to label and image cell populations in three dimensions. The ability to achieve this deep into intact specimens is limited by light scattering. Modern technologies, such as two-photon excitation fluorescence microscopy, allow examination of structures at distances of hundreds of micrometers below the surface but are insufficient to image and reconstruct large cell populations that are millimeters in scale and deeper below the surface. Whereas light scattering can be reduced by optical clearing, most of these reagents exhibit limitations such as the quenching of fluorescence. Recently, a clearing agent that spectacularly alleviates these major limitations was developed by Hiroshi Hama, Hiroshi Kurokawa, Hiroyuki Kawano, Ryoko Ando, Tomomi Shimogori, Hisayori Noda, Kiyoko Fukami, Asako Sakaue-Sawano, and Atsushi Miyawaki. They developed a clearing reagent called Scale that renders mouse brains and embryos transparent while completely preserving fluorescent signals from labeled cells!