Research / 2022 / Article / Fig 3

Research Article

Glymphatic System and Subsidiary Pathways Drive Nanoparticles Away from the Brain

Figure 3

(a) Illustration of i.c. injection of bulk AuNCs for separate investigation on the elimination. The brains were obtained at 5 or 30 min post injection to capture the dominant excreting phase. (b) Three dimensions (3D) reconstructions of confocal images to show the colocalization of AuNCs (green and red), collagen IV (blue) and α-SMA (pink). The images were captured every 2.5 μm for about 50 μm before 3D reconstruction. The hollow arrows indicate the ladder-like structure formed by AuNCs, while the solid arrows indicate the capillary veins without smooth muscle. (c-d) The TEM images of the WT mice brain received i.c. administration of AuNC@BSA and AuNC@GSH (30 min), respectively. The black arrows indicate the AuNCs in the basement membrane for glymphatic drainage, while the white arrows indicate the astrocytes end-feet, where the AuNCs entered the glymphatic system through high-expressed AQP4 protein. En = endothelia cells, As = astrocytes end-feet, Nu = the nuclei of endothelia cells, TJ = tight junction of endothelia cells, Pe = pericytes, BM = basement membrane.