Simultaneous\nMapping of the Nanoscale Organization\nand Redox State of Extracellular Space in Living Brain Tissue

The\nspatial organization characteristics and redox status of the\nextracellular space (ECS) are crucial in the development of brain\ndiseases. However, it remains a challenge to simultaneously capture\ndynamic changes in microstructural features and redox states at the\nsubmicron level within the ECS. Here, we developed a reversible glutathione\n(GSH)-responsive nanoprobe (RGN) for mapping the spatial organization\nfeatures and redox status of the ECS in brain tissues with nanoscale\nresolution. The RGN is composed of polymer nanoparticles modified\nwith GSH-responsive molecules and amino-functionalized methoxypoly(ethylene\nglycol), which exhibit exceptional single-particle brightness and\nexcellent free diffusion capability in the ECS of brain tissues. Tracking\nsingle RGNs in acute brain slices allowed us to dynamically map spatial\norganizational features and redox levels within the ECS of brain tissues\nin disease models. This provides a powerful super-resolution imaging\nmethod that offers a potential opportunity to study the dynamic changes\nin the ECS microenvironment and to understand the physiological and\npathological roles of the ECS in vivo.