Fig. 1

Utilizing NIR-II nanoprobes for high-contrast imaging of the CSF flow along PVS. a-b Schematic representation of selective NIR-II fluorophores (BSA@IR-780 and QDs) as CSF tracers. Blue represents BSA protein. Orange represents IR-780 dye. Rose red represents CdS shell. Yellow represents PbS core. c The NIR-II tracers BSA@IR-780 and QDs demonstrated superior photostability compared to cyanine dyes. d The cartoon depicts the collection of images through the intact scalp. The schematic diagram was created by using the online software https://biorender.com. e–h Both BSA@IR-780 and QDs allowed for high-contrast imaging of CSF flow along the MCA through intact scalp. White scale bar: 2 mm. Fluorescence signal along the white dashed line inserted in e and g was collected. Fluorescence signal was normalized with the smallest signal value along the white dashed line. i The NIR-II tracer QDs enabled visualization of the size of the endfoot tube. White scale bar: 2 mm. Blue represents astrocytic endfeet. Pink represents vessel lumen. Green represents PVS. j Cross-sectional fluorescence signal along the white dashed line inserted in i was collected to quantify the size of the endfoot tube k.The colored dots indicating three adjacent regions were measured by using profiles tool in Fiji software