Simultaneous Mapping of the Nanoscale Organization and Redox State of Extracellular Space in Living Brain Tissue.

The spatial organization characteristics and redox status of the extracellular space (ECS) are crucial in the development of brain diseases. However, it remains a challenge to simultaneously capture dynamic changes in microstructural features and redox states at the submicron level within the ECS. Here, we developed a reversible glutathione (GSH)-responsive nanoprobe (RGN) for mapping the spatial organization features and redox status of the ECS in brain tissues with nanoscale resolution. The RGN is composed of polymer nanoparticles modified with GSH-responsive molecules and amino-functionalized methoxypoly(ethylene glycol), which exhibit exceptional single-particle brightness and excellent free diffusion capability in the ECS of brain tissues. Tracking single RGNs in acute brain slices allowed us to dynamically map spatial organizational features and redox levels within the ECS of brain tissues in disease models. This provides a powerful super-resolution imaging method that offers a potential opportunity to study the dynamic changes in the ECS microenvironment and to understand the physiological and pathological roles of the ECS in vivo.